I suffer a problem from ads I have not seen in these comments. Us older, set-in-our-ways, folks don't buy a new phone or slab everytime a new release comes on the market. If the one we have still works, we still use it. The iPad I am now on is several years old. It does everything I want it to do (which isn't much). I downlad upgrades wherever I am notified of one. It is rock-solid when I am on professional sites like banking and brokerage services. It's rock-solid on this site. But some sites are totally useless. They lock up, freeze, and frequently crash, causing the page to reload. Some crash Safari, itself. I suspect this must stem from bad coding in ads, or someone using routines in ads incompatible with older devices.
Weather dot com is horrid. The weather radar page is impossible to use. And it's maddening to see a special weather alert that you can't read because of constant page reloads (accuweather dot com is better, but very slow). And I've given up on the local newspaper and local tv station. Because of problems with their sites, I would never consider paying for premium service from either.
These ads aren't just costing their sponsors money. They are driving traffic away from some sites entirely.