I would say the Crash and Spyro games aged far better than Mario 64 visually (though all these games look primitive).
That's certainly gonna vary from person to person. To me, most PS1 games have aged extremely poorly. Want an example? Mario 64 is still getting copied in various aspects, but Final Fantasy 7 visual style isn't. Don't get me wrong, FF7 is a great game, just not visually after the year 2000.
I guess they could have sold at full price. But then you have to "play" with the price/sales scale. Do you sell 2 million at launch for $60 or 5 million at launch for $40? Could their market analysis have screwed up and cost them millions of dollars? Sure, that's always a risk. But we are talking with years of hindsight to benefit us. It's much easier to say something was obviously gonna be a success or failure with that advantage.
I bought both Crash and Spyro trilogies, but the only reason I got both at launch was because they weren't full price.