Yes, it might work great as 20 teams of 5. No, not probably the way most people would do it.
It's not a matter of management, it's a matter of self-organization. People are not fungible like money. They are also not robots. So you just can't "manage" them or slice them into various groups and expect it to work well. You also can't take one giant problem and create 20 teams and expect them all to decompose it and solve it optimally without a lot of guidance. The things that work are counter-intuitive and the things that seem like they should work actually create a lot of friction and waste.
Put differently, there are a ton of startups that never made the leap from a 5-person team to a 100-person small dev shop. There are really good reasons for that -- and those are people who have been working together for years.
It's not a matter of management, it's a matter of self-organization. People are not fungible like money. They are also not robots. So you just can't "manage" them or slice them into various groups and expect it to work well. You also can't take one giant problem and create 20 teams and expect them all to decompose it and solve it optimally without a lot of guidance. The things that work are counter-intuitive and the things that seem like they should work actually create a lot of friction and waste.
Put differently, there are a ton of startups that never made the leap from a 5-person team to a 100-person small dev shop. There are really good reasons for that -- and those are people who have been working together for years.