To start with, I think it is great that CircleCI appears to be transparent and genuine in what is going on. On top of that, I think it’s unlikely that this will have a significant affect on their buttom line at the end of the year. Many people will decide it’s too expensive to move away from them, is my guess.
That being said, I think this really crap. I believe using CircleCI would be a bad idea. They appear to not have any capacity awareness. Their product is a hosted service, if you have no capacity awareness then what are you doing running a hosted service? Shit happens, maybe it’s easy to be Monday night quarterback, but, from the outside, it seems like they have focused on growing more than delivering a quality product.
As you said, once you choose CircleCI, it will take a lot to move away from them. Therefore it makes sense to “[focus] on growing more than delivering a quality product” because it is a land grab type of market.