I wouldn't be surprised to find that even the cheap Samsung Galaxy S3 mini I bought for 650 ILS (about $175) a month ago has more power than an 1970's mainframe. Again same OS family (Android which is also of the Unix family). Semiconductor technology advanced in great strides since the 1970's...
Hell, I started using a home computer in 1992, it was a 386 SX, 25MHz with 4MB of RAM (which was A LOT - "why the hell do you need more than 1 MB" we were asked by the vendor) and 120 MB of hard-drive space. It cost us about 6,000 ILS (about $2,000 back then, maybe even $2,500) with peripherals. My phone cost a tiny fraction of that and has memory and storage space greater by two orders of magnitude.
I don't think anyone back then in 1977 could've predicted the great increase in computing power and the massive reduction in computing power cost in the next 38 years and its effects on society (cue to the TL11 "Hand Computer" which costs Cr1,000 and is probably imagined as less powerful than my old TL7.5 Nokia phone).