CORRECTION: I stated Bioshock 4 was gonna be 20 years after the original but it’s at the same time, 1960s. My bad! Brain malfunction. Are you more excited for BioShock 4 or Ken Levine’s next game?
Bioshock 1 does take place in 1960, but Rapture is aesthetically 20s-50s. So it's easy to misinterpret the time period. You didn't actually see 1960s tech till Bioshock 2 when some of the characters had colored photos for their audiologs. And Robert Porters office looks very 60s mainly because he was ahead of his time in Rapture.
I honestly think Bioshock Infinite, in terms of gameplay was a downgrade from Bioshock 2. I can't belive I'm saying this but there were too many weapons in Infinate (although Burial at Sea was just fine with that) and I felt aesthetically Infinate made it look too much like if its from a multilayer game (brightly colored ammo, 2 weapons max and 2 switchable vigour at the time was annoying) What Irrational should have done is play Bioshock 2 and ask themselves where to go on from here. When I play Infinite I can't help but think, while it's a good game, it could have been loads better.
infinite is absolutely my favorite bioshock game just because of the story, the first and second do have a better gameplay but I can’t help but love infinites story!