99.9% of the people won't buy it for what it would cost to do it right. Most would buy an entire vehicle with lower mileage (compared to theirs) engine, swap and be done with it .. or just go with reman and roll the dice.
Are you going to do all the small nitty girtty work (that all adds up both timewise and costwise) to swap any those engines in, while also making sure you have a functional working suspension without doing shit compromises just to fit the engine in? If not you, are you prepared to pay what it would take to someone that is capable of doing it right?
What are you replacing it with, if any, for a daily driver?

I think the challenge with older vehicles is that even if you are OK initially, in the longer run you have to accept the compromises in terms of size/power/comforts/modern_amenities and it's a very conscious choice that you have to make for a daily driver (not talking about special cars like your K10 here).