Introduction
Recently I was out for a walk and I think I convinced myself that any given asic owner should theoretically make more money by pointing their asic at a hashrate market instead of directly at a particular pool, but only if there is no broker.
When I began thinking that way, there was something counterintuitive about it, which I'd like to address first.
Definitions
I'll start by defining three terms: "Owner" refers to a person who owns an asic and lists it for rent on a hashrate market. "Renter" refers to a person who visits a hashrate market and pays to temporarily rent someone else's asic. "Broker" refers to a person who runs a hashrate market — e.g. whoever bought the domain name, assuming it has a website.
Counterintuition
The counterintuitive thing about saying "hashrate markets are theoretically more efficient than pools" is that it seems to ignore the inefficiencies inherent to renting. Renters are incentivized to rent an asic if and only if they can put it to some use that is worth more than they're paying to rent it. That turns them into a kind of middleman: instead of the owner making all the money, the owner's machine is pointed at something paying X sats to the renter, and the renter is paying the owner an amount presumably slightly less than X sats, while keeping the rest. That must be less efficient for the owner than if he just pointed his asic directly at whatever endpoint the renter is pointing it at, and kept 100% of the earnings.
Austrian economics
But there's a problem with that idea, and I think it's related to an idea from the Austrian school of economics: no single actor has knowledge of all market conditions, especially given that they change from moment to moment. Consequently, there cannot be a settled and permanent "fair price" for any good or service. The fair price of a good or service depends at least in part on variable market conditions.
When an owner points their asic at a particular pool, the rate they receive might be the optimum rate available at the moment they chose that pool, or so close to it that the difference is negligible. But market conditions change moment to moment, so even if you chose well in the morning, by noon there may be a better rate at another pool.
You could try to find the best rate by using software to constantly poll every pool you know about, do the math to reassess the optimum rate, and change your stratum endpoint every few seconds, if necessary. But this procedure can never be perfect. Some pools require KYC, which is very difficult to automate; some don't let you use them if you're in certain countries, e.g. due to sanctions; and new pools spring up all the time, often with temporarily discounted or zero admin fees.
Even if you had some way of letting new pools tell your software about them so it can factor them into its calculations, why would you trust a tiny, new pool? Pools can rug you by never paying you anything, and it's particularly easy for small pools to do that because no one's ever heard of them, they have no reputation to burn. It's hard to automate decisions where you don't know who to trust.
How hashrate markets help
Theoretically, a hashrate market can improve this situation, especially due to the following insight: you can rent from yourself. If you do good research at the beginning and discover that Antpool has the best payouts right now, at 5000 sats per day for your equipment, you can still point your asic at a hashrate market instead, then set your "minimum rate" to 5000 sats per day, and rent from yourself. Then point that self-rented asic at Antpool, just like you were going to do, and get the optimum rate you found.
But here's the advantage: if you were wrong, due to not having perfect knowledge of market conditions, and someone else knows better than you, that person can come to the hashrate market, knowing there's a better place where an asic like yours can earn 6000 sats per day. He can rent your asic for 5500 sats per day, which beats your rate, and it's a win-win. He gets to redirect your asic to an endpoint that pays more, you get more than you would have, and he gets some too.
This is also the case for pools that compete with Antpool. Do the people running Ocean know you are missing out because their pool pays out more than Antpool? Then they can rent your asic for an amount higher than what Antpool is paying you, but less than what they believe they themselves (Ocean) will earn, and they get to keep the difference.
Of course, if you "find out" the new best place is Ocean (for example), you can raise your own minimum rate to whatever Ocean pays out, and, if no one beats your new minimum rate, you can rent from yourself, and point your asic at Ocean til someone does beat that rate. Theoretically, you can always do this as long as your asic is pointed at a hashrate market where you can rent from yourself if necessary.
The broker problem
But there is a problem with such a theory: the broker. Brokers such as Nicehash charge a 3% fee. So you can't just "rent from yourself" on such a pool with no downside. If you put 50,000 sats into Nicehash, and "rent from yourself" for 10 days, pointing the asic at Antpool who pays out 5k sats per day, you aren't guaranteed to get 50,000 sats out. In fact, you’re likely to only get 48,500 sats out, due to Nicehash's 3% fee.
You might still get lucky — someone might come along who knows a better place than you, one that pays out 6000 sats per day, so he rents your asic for 5500 sats per day and keeps the difference. Then you'll make 53,350 sats, which is more than you put in. But you can't guarantee that such a person will come along, so it's a risk, and that risk exists entirely due to the fees charged by the broker. Plus there are other risks of using such a broker, such as custodial risk.
Conclusion
So, if anyone can make a "brokerless" hashrate market that works as well as an ordinary one, with no custodian, and if you can set a minimum price for your unit, and rent it from yourself while you wait for a higher bidder, then I think, based on the above reasoning, it would theoretically be a more profitable place to point your rig than if you pointed it directly at a mining pool. Because of an insight I learned from Austrian economics. Do not presume yourself to be the one man who knows the best rate, for it is very unlikely that you are that man, and it is even rarer to be that man for long. Give the market freedom to find you an optimized rate, and learn from it.