They easily had that technology, just used it more judiciously, requiring warrants easily obtained. And once in position, it was unlawful to interfere with such devices, if you discovered them. Public places and businesses did adopt much camera security during that time.
At that time, if you made more than four long distance phone calls a month, one of them would have been monitored by the NSA.
The popularity of the Internet was a major setback to such monitoring, then public domain encryption.
The successful conclusion of the (cold) war with Eastasia also caused much chaos in the surveillance networks.
So it has not been a straight line progression. But things really picked up after Reagan.
Sorry, but the ability to put in wiretaps or cameras with a warrant, even if it’s too easy to get, is not equivalent to ubiquitous, warrantless, constant monitoring of every domicile. Businesses and public spaces are irrelevant, since that is not governmental intrusion.
As for the NSA, I believe what you are referring to is international calls, not long distance calls. At least, I’ve never seen a single reference to the NSA monitoring domestic long distance calls (legitimately at least), prior to the 9/11 era.
Sure, there has been a progression, but we are not even today at the level of monitoring that happened in 1984. Britain is closer, but even they are far from it.