If there was no Beeb, other providers would increase their advertising to US levels. Believe me, you don’t want that.
If you are watching a streaming or catch-up service, then there are simple ways to kill the advertising stone dead so you never have to sit through it in any case. It's dependent upon whether you are watching via a Smart TV app, or via browser, and if it's the latter you can watch pretty much anything without ever having to sit through an ad, including ITV, Channel 4 etc.
Not to mention all those US series that are written by committee. We only tend to get the best here - but the amount of dross produced in the US is unreal
I don't see the relevance unless you are suggesting that changing the income model for the BBC would inevitably mean no more BBC produced content and everything they broadcast being bought in from US commercial producers. I can't see this being the case when they are already bleating about a decline in licence revenue but still churning out precisely the same content. A more secure revenue stream shouldn't change that.
If you don't watch that stuff in the first place, then this is neither here nor there, because even in this doomsday scenario the BBC would just be yet another channel showing committee-written nonsense which you don't watch anyway, and some of us don't watch the BBC as it is.