It's a pity but they've also never said anything to the contrary, I think it's just that people got over-excited by what MS were doing and showing (the vast majority of the Series X coverage so far has been about Xbox One games after all) and assumed Sony's approach would be similar. For me, it's always seemed apparent that Sony's extent of implementing backwards compatibility was to get the games working and that's about it.
That's not to say that they can't or won't improve things via software updates later down the line though, but I won't personally hold my breath and I haven't pre-ordered a PS5 expecting my existing games catalogue to suddenly be transformed.