Less than what? Perfect? Less than I deserve? Less than what other people think I deserve?

The question isn't clear enough.

And the word "settle" doesn't settle well with me.

Settle ? Why ? You only pay later...

A good (or even so so) book always works for me.

Well, there's alone and there's lonely, and I'd rather be alone than with someone I feel lonely being with.

That's why yall are alone . Lol

The choices aren't applicable, assuming - as is typical in the US - that everyone is looking for a conventional sexual permanent partner in a recognized romantic configuration.

I like having anyone in my life with whom I enjoy interacting, from wild hawks and coyote pack friends to people I see routinely. I'd love to go hiking, to the zoo, read books together, joke around, and snuggle with someone I trust, and love to be with.

But a permanent relationship can problematic, since seniors are typically set in their ways, housing, location near their grandchildren, etc. so someone would have to give up their lives to make a conventional "couple."

No, never! That sums it up perfectly...I am never going to settle for less than I had with my husband, pale imitations of the “real thing” have no appeal!

I think this question is flawed because one never really knows what one is getting into until months or years later. The totality of a person is not revealed immediately and especially when the blinders called lust shade one's view.
This is not like shopping for a new grill on Amazon, where you can check all the dimensions, the specs and even read prior customer reviews before deciding.
It's more like having 3 minutes to pick the next book to read at Barnes and Noble. There's the cover illustration, the picture of the author, and you can flip through a few pages, but that's all you get. Wing it.

I have settled in past relationships and am
no longer willing to do it, sexually or intellectually. I have wonderful friendships that sustain me while I search for a partner, so I am fortunate to not be lonely.

I’ve lived alone many more years than I’ve lived with someone. I’m fine alone and wouldn’t give it up just to avoid being alone.

I actually like being alone about half the time. But, the complete absence of any kind of intimacy it too high a price to pay for that limited solitude. Certainly there should be some middle ground.

I guess it depends on the parameters of settling. I was raised that I could be missing "Mr. Right" if I was wasting time with "Mr Wrong." But I've found that there are a lot of variations on Mr Right that can make the search less lonely.

The American fairy tail version of what we are supposed to expect in a partner has me so distorted I don't even know what settling is.

I think we all have to settle in many minor and larger ways to be in any relationship. The question is if you consider it settling or just how much one is willing to compromise.