Budget Limit
The problem is the budget limit you have while trying to upgrade facilities.
I see the purpose of that, it does prevent new or not experienced players to fall into economic problems early on but instead of imposing it to everyone, there should be a way to disable it.
Like something to tick in the settings or even a pop up warning us. Because it is VERY annoying and when it starts to cost a lot, it slows our whole progression and for a longer time each level.
This thing is and should be taken as a protection but not as a requirement. At the moment it is only here to double the cost of every facilities, protects new players and annoys others regarding progression.
Regards.
Edit: Removed "was added to the game recently" since it was added since the beta.