I would expect at least some evolutionary pressure to get rid of unused things in your body. Let's just take the appendix as an example because it's probably the most common "you don't actually need this" thing that people know about.
Some appendixes burst. Sometimes this kills people. Sometimes this happens before that person has been able to reproduce. Wouldn't this cause selection for people who at the very least don't have bursting appendixes (appendices just sounds wrong to my inner narrator in this context), but also for people who have smaller ones. Over time this pressure would decrease but shouldn't it theoretically over many many generations result in smaller and smaller, eventually disappearing, appendixes?
I would think so. Who says that's not happening now? It seems reasonable that evolutionary pressure can be strong enough to have a significant impact in 1-2 generations (for example due to the introduction of a new environmental threat) or weak enough to take thousands of generations.
Exploits need to plug into a business plan. Like any business plan there has to be somewhere that money gets extracted and that money needs to be more than the exploit cost & infrastructure costs & a risk premium.
If you can’t trivially say how the exploit explicitly gets turned into cash you probably are on the wrong track. Doubly so if it’s not a known standard and commoditized way that’s happened before.
Or, you know, develop a new "business plan" around an exploit.