> I have to doubt this is a primary factor
Time and money are indeed a factor, micro transactions typically are used to continue "live services" of a game, and don't get counted towards recouping development costs. (at least in Ubisoft).
> if it were then developers would make more single player games
We can, and do, but sometimes to create the game you want other players involved. Imagine a NPC only For Honour or Rainbow Six: Siege.. that would be very boring.
> but everyone wants to make online games
Because there can be more interesting games than just "go here, kill boss, go here, loot thing", you can have genuinely unique experiences on every play through with online and networked games.
> with microtransactions
To cover the cost of the servers and staff required to update/fix the game, usually.
This is a complex one because people are so polarised by micro transactions. I (and incidentally, my studio) are convinced that they _MUST_ be optional, they can offer no advantage in game.
We used to have the policy that you must be able to earn that cosmetic with a realistic amount of in-game time (which is contradictory for us because more in-game time = less money, and obviously we "lost" the revenue of a player not buying it, but that goes without saying).
Given that we release buggy mess games, you might argue that we would need less micro transactions if we just did a good job in the first place, but obviously we try our best to make decent games. I think it's dangerously arrogant to assume that 60 developers working on engine and game server code are all less intelligent than you are- and there definitely isn't malice, most game developers are gamers themselves otherwise the complexity, stress and time spent would definitely not be worth it.
So I'm not sure why people are so outwardly hostile to game developers, the alternative is that we spend longer and charge more for games, but people don't like that either, so at some point the market has to make up it's mind about whether it can accept rushed products that have improvements year on year, no or marginal improvements year on year (ala Fifa, Call of Duty) or pay more.
There is no magic here, unless we bring back slavery.
Seems like not many people choose that option though. :)
I can't promise that anything will change, because we can't easily qualify how much demand there would be for such a feature. But, I can tell the people I know.