you'd end up with a call center larger than most cities. It's not feasible.
If firms had a base degree of customer support they were expected to provide, they would still exist. They would just not be as profitable, but customers would be better off.
I seem to remember there was a time when S/W was also designed with the aim to be easy to use, so that the need for support was reduced. It feels like the lesson learned was to keep costs low, not to ensure users were ok.
Sorry, you can't buy an iPhone because Apple has got too many customers.
Sorry, you can't have a GMail account because Google has too many customers.
If you could be profitable with 50 customers providing excellent support, you can be MORE profitable spreading that excellent support across a larger customer base.
Just because none of the big corpos choose to do this does not mean it isn't possible. It's JUST greed.