> they're at the mercy of the transmission market
There is no such thing as a transmission market. The grid is a regional monopoly, and it doesn't "market" its capacity.
The issue here is that when too much power runs through a line, if you don't turn it off, it does [1]. Building more lines isn't exactly fast, or cheap, and it wasn't really a major focus of the people setting up subsidies for new production.
> It's not their problem because .. it really isn't their problem and they can't solve it.
It's not their problem because their subsidies scheme means they will get paid anyway.
[1]: https://www.reddit.com/media?url=https%3A%2F%2Fpreview.redd....