It's relatively trivial to do a minor refurb to replace and realign hammers/felts, rather more expensive to replace the tunings pegs and strings, quite a big deal to do all the above and replace the soundboard too.
Gf's instrument is getting near to needing a complete rebuild, which we're estimating will cost around £6k and take a few months.
I can appreciate the interest in digital instruments, but nothing sounds close to the sonic richness, weight, projection, and detail of the real thing. You certainly can't play classical piano music on a sampled keyboard and have it fill a concert hall the way you can with a Steinway Model D.
I saw an organ in the Netherlands that dates to the 1700's, and has been played by many legendary composers (including Haydn and Mozart, IIRC). While it's obviously seen continuous maintenance, it's still playable and used for performances today.
Some music schools have contracts with Steinway where they get all-new instruments every year, which are sold back to Steinway at the end of the year who sells them as used instruments. I'd imagine (but have no evidence) that music schools in general are one of the largest consumers of pianos. At our undergrad institution of ~200 majors, we have probably 30-40 pianos in the building. My graduate school probably had upwards of 200, and employed 3 full-time piano technicians to maintain them.