Thinkpads are built for business and there is a healthy 3rd party market (and first party market as well) for parts. I’d say your general observation about planned obselence is true, but not so much for thinkpads.
Specs wise, I think my x220 kicks the crap out of all Chromebooks.
Whatever happens, make sure you budget for a nice monitor to hook it to… I don’t know of many laptop screens that are great for photo editing 