Many people here are mistaking remasters and remakes.
Anyway my answer for this would be... They are not the same games, the only exemple of a remake that I felt is really worst than the original is Twin Snakes. The art direction of every MGS series and the cinematic are very classy, very artistic, there's a vision. Twin Snakes is just a b series level of direction and art direction, it was quite ridiculous.
But all other remakes... Well they are "modernized" versions. Let's take the RE2/3/4 remakes, they are all AWESOME games, top tier in their genre, but it doesn't make the OGs unplayable to me, they are different games and I can have as much fun playing original RE2 than the remake, it's just different feeling.
I think OG games that are unplayable are games than you didn't experience on their time, or worst, games that came out when you weren't even born. I am born just when the Atari 2600 died, and even though I played some Pitfall at a moment of my life and recognized it is a great game, I've no... "inner feeling" for it. But NES games and even better, SNES or PS1 games I feel sooo good playing them, I could spend my life playing just those.
So yeah I love most remakes of games I originally loved (RE1/2/3/4, Demon's Souls, SotC, Dead Space, etc) but I do also love to play the OGs.