I assume the suggestion isn't that Nintendo should give the games away. Just that if you buy a game on the Switch you shouldn't have to buy it again when you upgrade to their next console.
I certainly know that I'd be loading up if they made everything available in perpetuity.
And thinking of how many people want to get get into a series but simply can't because there's no real way for them to. Nintendo isn't really even doing VC this generation. So they're turning to emulation, if they're technical enough.
I won't buy virtual console stuff because it won't carry over.
I'd happily buy their whole catalog if I knew it was mine forever.