Even with the proposed increase, it'd be one of the lowest in the G7. And you're right, it's only paid on profits so it couldn't stop a company being profitable. Fair play to
@BoroMart though he's said the same himself now.
It can, most small businesses pay out dividends, rather than PAYE, and there are also problems with profits being locked in assets which
So you can declare a 50k "profit", by paying the company owner nothing. So then when the company owner takes 50k for 80 hours a week and a load of stress, this comes after the "profit line", so in reality, the business actually loses 10k corp tax and the 50k too, so is now actually at a 10k net loss, despite declaring a 50k "profit".
If this ended up being 100k profit, then they pay 50k to the director and pay corp tax they end up with 30k left from 100k "profit", if they have two directors it's 20k down. Businesses can be "profitable" but not cash flow positive, they can be massively cash flow negative.
You can also show profits because you're paying off assets too, but this gets complicated. The problem then is if the assets later devalue (like machinery and vehicles) you can end in a situation where you have loads of old kit and are showing massive profits but have no more money in the bank. It's all tied up in gear. If you sell the gear you need to replace it so you lose, by buying new for old when you wouldn't otherwise need to. If you just sell it then you have no gear to do any work so you go under. If you don't sell then you just get drained by corp tax, then when you do finally need new gear you have no extra cash, so have to resort to financing again.
It's messed up, it's like a system designed to encourage overspending, and penalise those that look after their equipment. They want people to just keep buying and buying new gear on finance.