I love retro gaming, I grew up through the 80's and 90's so I have fond memories of playing games during the 8, 16 and 32 bit generations. I do agree with you though that nostalgia for these eras does cloud our vision and distorts our memories of what those games really were and the inconveniences they presented.
Don't get me wrong, I still love revisiting the classics like Super Mario Bros. and Castlevania but honestly, like you said, they're outshone by what modern games are doing these days. Sure they can be heralded as being the advent of many of the core concepts we see in games today, but with that comes many of the annoyances that were weeded out in later iterations.
This is much more apparent when you have no nostalgia for a particular game. It's faults seem that much more noticeable.
One thing about this "retro zeitgeist" is the existence of "retro-snobbery" and the whole misconception that modern gaming is terrible. Or that retro games just did it better. It's really a shame because there are many modern games that are amazing, and to not give them a chance means you'd really be missing out.
I think it's important to appreciate what devs are trying to do these days and experience the advances in this wonderful medium. Of course, it's also difficult to appreciate the advances if you don't have any background of what was there before. It's a balancing act of reliving the past and embracing the present.
I mean, in 20 years the games of today will be considered retro, and you can't have nostalgia without the memories of playing those games to go along with it.