I had a sportster with the engine solidly mounted to the fame. Drove it over 10,000 miles one summer. It was totally fine. Nothing broke or rattled loose.
Anecdotally, I got my 2006 GSXR1000 to 130 000km(80 000 miles). I only sold it because I was moving into a bigger city. Having to trawl around in 1st using the clutch most of the time was not appealing.
I ride commuter most days and used to do on weekends. I like the 2nd hand market having so many low mileage bikes.
While I am not about to make disparaging remarks on Harleys reliability, I won't buy one because I like my bikes to perform.
Also, amongst my friends the "Boomer cosplay stores" comment rings true. Nothing inherently wrong with that I guess but not my crowd. I mean, people buy italian supercars to pose down slow streets with too. Your money, do what you want.
My sportster went about 30K miles before it was stolen so can't say how far it would go. But insurance gave me more than I paid for it brand new, which you can't say about Japanese bikes.