In 1960 I only knew of one ham repeater and it was only a temporary repeater on mount Vaca. Each year there was a boat race that
started in Rio Vista, CA and went to Colusa in one day and then some would go on up all the way to Redding the next day. Many of the boats that started would not make it so check points with ham radio scattered up the river for the safety and assistance of the boat operators.
The airline distance between Rio Vista and Redding is close to 200 miles. The mount Vaca 2 meter AM repeater allowed amateur radio communications over the whole distance.
By 1962 when I joined the Coast Guard there were commercial repeaters but I still knew of no amateur repeaters except the one I already mentioned. When I got out of the Coast Guard in 1966 a few 2 meter FM repeaters were starting to show up around Sacramento. There were other repeaters I am just speaking of the ones I knew about. 1974 when I graduated from Collage there were two meter FM repeaters in abundance.
Arthur M. Gentry, W6MEP began experimenting with the concept of a radio repeater in the late 1940s but it was not until the early 50s that he was able to put his AM repeater on top of Mount Lee overlooking Los Angeles with the call of K6MYK. For those of you who don’t know Mount Lee is the one that has the big Hollywood sign that is so frequently seen in movies and on TV. The repeater continued to operate using AM until the early 1970s
Other AM Repeaters began to spring up but the early 1960s. It was at that time that the commercial FM all vacuum tube radios like the Motorola Twin V were being traded up to transistor units with tube driver and final like the Motorola Motrack. This made a lot of vacuum tube FM equipment available for ham use
for a very low cost. Most of these units could easily be switched to ham frequencies by changing crystals and retuning. FM is much more effective for repeater use then AM so the switch to FM was natural.
There seems to be no argument that Arthur W6MEP built the first ham radio repeater but whether or not this had any effect on the advent of commercial repeaters seems to be aloof.