There's been a lotta technology developed in the last 50 years...I have a 1991 magazine that is a compilation of road tests from the old Hi-Performance Cars magazine. The fastest 1/4 mile time was a 12.5 posted by Joe Oldham's 1969 Motion Performance big block Camaro- with 4.10 gears, uncapped headers and slicks. Aside from that car most of the others put up 1/4 mile ETs in the 13.5-14.5 second range. Those times are definitely on the slow side of average for performance cars these days. My 2007 Mazdaspeed 3 could run in the low 14 second range and trap 100 mph all day long- and that's with a 2.3 liter turbo that averaged 26+ mpg over the 8 years and 158,000 miles I had it. My M235i returned similar fuel economy but ran the 1/4 mile in 12.9 sec @ 109 mph. Even my wife's X1 can run the quarter in 14.6 sec @ 95 mph(a bit faster than my 1988 M6 when it was stock). That said, I love the musclecars from that era; if I had the money and garage space I'd have a Boss 302, an XR7-G, an AAR Cuda, a GSX, and a Ram Air IV Judge- but I still definitely believe that "the good old days" are NOW.
As you posted, a 12 or 13 second car back in the day had a pretty short gear ratio to get it moving... But was lousy on the freeway.
Heck, until 1967 most GM vehicles ran around on 2 speed automatics that needed rebuild at 60K. Today an F-150 has a 10 speed tranny!
Today's cars can do it all. And might even make it to 300K...