So not really disagreeing with you pre se - more just adding my 2 cents....
In the days before piracy and then streaming, a lot of artists didn't play live. Song writers made a decent living staying at home, writing songs and not performing. Burt Bacharach for example is a terrible singer.
Burt Bacharach isn't really a good example for the point you are making.
Why and when did Burt choose to perform live?
First money was never the motivator at all. After his incredible early 60's rise to the top of the songwriter heap - and the giant disaster that happened at pinnacle of that rise (The big budget flop of the musical remake of the classic movie, "Lost Horizions" - Burt was to a great degree burnt out. Basically disenchanted with continuing to the pursuit of writing hit songs that had driven him throughout the previous 15 years. So he retreated into sort-of retirement... playing tennis.... ultimately bored out of his mind. Some close friends kept saying "Burt, why don't get out and play - like play Vegas". To which he would scoff - "and do what? Go out on stage and write a song???".
But the fact is - before Burt was the successful songwriter - he was top level pianist and musical director/conductor for some really big acts. And he was a far more than competent arranger. So taking a big pile of his hit songs - he concocted a full length show with full orchestra featuring him playing piano, conducting new arrangements and medleys of his hits. Lots were done as instrumentals - with bits of vocal interjections made by a trio of girl singers.... with Burt singing a bit here and there. Choosing bits that he could sing effectively in a sort of quirky song-writer singing their own stuff... all Bob Dylan, Leonard Cohen, etc.... "Writer's prerogative" he used to refer to it as.
And so, from about '68 to the early 80's - he performed live and made albums in this same sort of style as an artist for A&M Records.
Then it was future wife, Carole Bayer Sager, that got him to re-engage with pursuing writing pop hits - leading to "That's What Friends Are For", "On My Own", "Arthur's Theme", etc.
And so he remained engaged in pursuing writing new stuff until his passing - but also had come to enjoy getting to share his songs directly with an audience as well. Along the way - the sort of orchestral instrumental approach was abandon in favor of a more pop style touring ensemble - with three lead singers, two keys, two horns, bass and drums. He still did appearances with orchestras - but it was now more like any pop act approving with an orchestra.
Personally I got to play in both eras - and found both challenging and rewarding - though any different ways.
None of which to say - that Burt wasn't a horrible singer.... he was. Just that it was never something he sold himself as - and his move to live playing far pre-dated the later shifts that our industry has gone through.
Kate Bush stopped playing live because she hated it. Kraftwerk and Steely dan didn't play live for years.
It is only with the collapse of income from records that people have 1) had to play live and 2) had to try and monetise social media like Youtube and Tik-Tok.
Reflecting on this last sentence. Looking back - I think the age you and I sort of came up in - where live performances had become primarily a way to market recordings. And where recordings were the primary generator of an artist's revenue may have actually historically been the anomaly.
I mean, of course, the onset of the technology of recording is what drove things to that place. Because obviously it hadn't been that way before.... since the day's of the troubadours - artists sang live "for their supper". Recording technology changed that.
And for awhile - for as long as the big companies controlled the entire process - recording, manufacturing, marketing and distribution (which they controlled because all aspects were expensive). But now, just as technology threatened to destroy the economic viability of live performance - which it basically did (Record companies routinely subsidized touring throughout the 70's and 80's). Now technology has stripped control of all aspects except probably marketing - and thus, just like the radio orchestras of old, we are suffering through a major upheaval.
I can't say I'm surprised - as the era of recording money totally dominating the industry was only around for 30 years, give or take.
None of which is to say it doesn't suck
Personally I preferred the old model where you didn't have to wade through a mountain of mediocrity to find something well done.