Have you seen this guy?

"If you ain't burning a hundred pounds of copper wire, and strippin' a hundred more. Where the fuck you at?"

This is my fav video about this topic:

https://bit.ly/3vvSou4

I really can't tell what's satire anymore.

I'm wondering if it's economical to strip out accessible copper pipes from older homes and replace with PEX.

Material wise? Sure if you do it yourself. Paying someone else to do the work though? Definitely not.

To rephrase: if you do it yourself and accept that you will be compensated less for your time than anyone you could employ to do it.