I don't think anybody in this thread suggests trying to use yeast strains so expansively. OTOH a brewer could use one or two lager strains to brew pretty much every lager style out there. You could use a single English strain for most if not all English styles. Etc.
We don't spend all that much time talking about those decisions as homebrewers because we're spoiled for yeast choices and it's easier to buy a strain that fits a recipe than modify a recipe to fit a strain.
I can only speak for myself, but if there were only 2 strains of yeast left, 34/70 and Nottingham, I'd be fine with it. I try countless yeast types because I can. Not because I'm forced to. Yes, if you want to brew certain styles they may require a different yeast. Whatever...
What bothers me about all of it is the wanton gouging in the yeast industry. Ok, I get it, if you make less yeast you need to charge a little more. Consider this.
If I go to the grocery store and buy tiny little packets of yeast for bread. They're $0.79 each or some insane number for each 7 gram pack. I look at the "Big" container and that's some perverse amount of money. I won't even quote because it's been so long since I looked, I don't even know what it costs there any more. So I go to King Arthur Flour online and a POUND of SAF Instant yeast is $6.99. And if I go to the Amish grocery store locally, there it's $4.99.
Have you looked at what it costs for a pound of dry brewers yeast lately? Anyone care to explain why bread yeast is 1/100th the price? ** (Unless of course you buy at the grocery store in small packs...).