Yeah, exclusives are hugely important and the gulf in sales numbers reflect it. Having a consistent stream of good quality exclusive games releasing does a lot to generate goodwill, and Sony really needed it after the PS3. Any attempt to dismiss these exclusive games as 'niche' or overrated is tantamount to pissing in the wind, as games that review well keep the public perception rising and units shifting. When all's said and done, the focus on the past and back compatibility is a distraction from the fact that the Xbox One is a sales failure, and its present and future don't look all that enticing either. They have done good PR work lately and have done well since the disastrous E3 2013 and launch phase, but it's nothing without new interesting games instead of the same old.
Having said that, I'm not interested in a PS1 Classic that doesn't play old discs. I have a big library of physical PS1 games and would like to play them on the Classic, otherwise there's no reason for me to replace my old region modded PS1. However, I think it will sell well as, simply put, the PS1 is one of the best consoles of all time. The classic console model is viable when your consoles have actual heritage and provenance, as Sony and Nintendo's early offerings do.