I don't need to do a long ride *every* week (but when I can, it sure feels good). Thing is, a long ride... is a long ride. And I've never done one *that* long - 160 miles is my longest. So this is all hypothetical.
I think that if you are riding fairly long every day and get to the point where 60 km is just a pretty normal activity, then cycling isn't a big exertion, so long isn't long. You still have to deal with things like chafing at some point... but with all that daily riding there would be calluses!
I didn't find 160 miles to be all that much longer than 100 (tho' the tailwind the whole way helped).