For me, it isn't just about BC or making things available, it's about the condition they are presented in. PS1 to PS2 BC was admittedly pretty great. 2 to 3, though, was a mess right from the get go. People remember the early PS3s as all being BC, but they weren't. The 40GB models never played PS2 games, only PS1 games. But even after that, A01 models and E01 models, while both backwards compatible, have different performance and image quality when playing PS2 games. And models after that just don't play PS2 games. As for PS1 games, even those are inconsistent. There are PS Classics (the ones sold digitally on PSN for PS3) that look and perform differently than the disc version of the same game!
Nintendo may not have the best record with BC, but when they do it, they tend to skew towards the better. They would have never released a mini console in the state the Playstation Classic was in. And GC to Wii and Wii to WiiU BC was spot on. GB to GBC and GBC to GBA, and GBA to DS, and DS to 3DS was also great. Actually, I might have to amend my statement about them not having the best track record with BC. They have the most BC consoles out there, and they all perform as expected.
What I think it all boils down to, is that I don't believe Playstation respects it's own history in the same way Nintendo does.