Thought about it a bit: would it be better for Sony to offer a-la carte options for stacking various tiers together?
For example, say the highest tier is Tier 3 and offers everything, but you only want BC streaming for PS1/2/3/PSP/Vita games. With the usual method you'd have to also sub for other things you might not want, but couldn't they just offer that streaming option as its own tier at a lower price? Especially if you literally just want the BC streaming, and not PS4/5 streaming or online play (for whatever reason)?
I think that could give subscribers more flexibility in their options, and overall get more subscribers that way. Comparatively, one of the weaknesses for GamePass (especially in mobile) is that xCloud is tied to GamePass Ultimate, meaning by default you have to pay a more expensive price just to get the feature specific for your use-case, and you end up paying for stuff you otherwise don't want or just can't use.
Which is kind of relic of the television model when you think about it; I know Microsoft have said they will offer xCloud on its own at a future date, but it would be great if Sony could leapfrog in that respect and just have things like online play, PS4/5 streaming, BC (pre-PS4) streaming, etc. as their own options that can be stacked a-la carte style. As for Day 1 1P games, I think they could do it for non-blockbuster 1P titles that maybe aren't a good fit for retail. Stuff like Destruction All-Stars or a new Parappa, for example (please make a new Parappa...actually, a new UmJammer would be better

). I can't see them doing Day 1 for games like Spiderman, Wolverine, TLOU etc. unless they treat them like rent-to-own VODs with monthly payment installments.
Otherwise such a service could end up unsustainable for them long-term.