Your concerns are typically addressed by:

1. Reserve pricing - if no ad is 'good enough', e.g. no advertiser is willing to bid above a certain threshold for you, then no ad is shown

2. ePCM pricing - Adsense predicts what the likelihood of clickthrough/conversion is for a given ad and user, and includes that in its auction algorithm. Roughly, eCPM bid = cost per click / probability of click. This addresses the typical problem of high CPC/CPA bid but low engagement probability ads crowding out otherwise good CPM-based ads.

In general responsible advertisers have aligned incentives with viewers. Intrusive or obnoxious (or malicious) advertisements hurt viewers, who are less likely to return.

I think a high reserve price is actually a really neat idea - you'd think that might have the knock-on consequence of reducing the attractiveness of adblockers, and furthermore of reducing viewer fatigue (so that the ads you do show have more impact). If you're smart enough, and take into account the "damage" to your relationship with the viewer when choosing an ad (i.e. aiming primarily for the ad the viewer is most likely to appreciate, and only secondarily other effects such as how likely they are to click and how much the advertiser is willing to pay), you might even be able to make ads the viewer actually wants to see; which in the long run is probably a very good place to be.

I wonder if part of the reason that never happened is simply that ads are in a sense "reserved" layout space that need to be filled consistently and cannot be filled later on (due to layout jumpiness).

I wish I had a better way to tell Google to raise my reservation price than blocking most ads I see, maybe pay for a higher one?

I just wanted to say that it’s actually nice not to be the only one who is harassed by forex trading ads around the web. Them and Mobile Strike are pretty much all of the ads I see. (I do have Adblock but can’t block for YouTube mobile etc.)

There are other apps for youtube. E.g. newpipe.