Weren't the AR2ax already getting old by 1970?
Nope, just getting into the second generation version with foam surround woofers and paper dome tweets that started in 1969 and went on well into the 1970's.
I have all of the Conumers Report books from the 50's through the late 70's (my parents had a subscription and never threw them out). They always had a large section dedicated to all types of electronic gear that was covered in their monthly magazine for the the year and I read them over and over again as a kid. Later on when I had enough scratch to buy decent used audio gear I already knew what to look for (although back then I would take whatever I could get