There’s a lovely post here by a man who tunes pianos, noting that
The finest pianos in the world were built about a hundred years ago. Due to evolution in engineering, exhaustion of raw materials, and flagging business standards, we will never see their like again. Some people may build very good pianos; new forms of the instrument may exceed (in narrow ways) the magnificent machines built a few decades either side of the year 1900. But, from a musical perspective, there will never be a “better” piano than the typical concert grand of a century ago.
The whole post is worth reading, if for no other reason than to get a glimpse into the world of a guy who knows pianos.
The article mentions supersonic flight as another thing that’s been lost, although I would argue the Concorde was always an expensive gimmick which was more likely to irritate the masses than please the elite. At least part of this judgment was based on living in a sonic boom test area in Kentucky around 1960. Sonic booms are loud and obnoxious, and it can hardly be a good thing to see your walls move (as my sister reported, who’s so deaf she can’t hear a sonic boom but only see it).
Public phone booths are another small loss. Cell phones are mostly better, but public phone booths provided a connection you could hear, and did not have batteries that died and didn’t much drop calls. Plus, people only called you from one when they had something worth paying 25 cents to say, not just because there were bored and needed you to entertain them.
There’s more things, but I risk being branded as a curmudgeon if I list too many. Besides, a lot of these are like public phone booths – replaced by something that is mostly better.