It would at the very least reduce the amount of it and select for advertising of a higher quality, cutting the noise a little.
If it does increase spending on things being advertised, the absence leaves us with more money for all those other things that are currently ad-supported.
If it doesn't, it's a scam.
If those things supported by ads would be literally unaffordable by the consumers if not for those ads, because the consumers are so poor they have no money to spend, the fork is still true; it's just that if those ads work then they push those already-poor consumers into debt for things they'd otherwise not buy because they couldn't afford, making them even poorer.
By definition it shows an issue where we have a process that tricks human minds into thinking they aren't paying for something, when as a collective, we pay more for a worse service than we would have if it existed in a alternate framework.
I've never even used free wifi that was ad supported, and I'm not aware of a situation where this is common.
Ad revenue is nowhere near enough to build the facilities necessary to play baseball, so little leagues are getting funding in a lot of other ways which could fill in the gaps if ad revenue were removed.
The simple fact is that we have lots of examples of ads being removed and economies puttering along just fine.