Magnatones were more expensive than Ampegs and Fenders. That made it hard to sell a Magnatone amp to a random musician wandering into a music shop. They did sound great, so professional musicians who valued that quality of sound could (and were) convinced that the premium price was worth it.
This is where name recognition via advertising and artist endorsements help sell amps (get customers to walk in and say "I want that Magnatone sound at any cost!") Enter Estey Public Relations. The best I can tell is that Saul Knazick was in charge of sales and marketing for most of the 1960s. He is usually the guy that is quoted in press releases for both organs and Magnatones.
The sixties were an incredible time of change in music culture. When reviewing it from fifty years later, its easy to see what worked and what didn't, and maybe easy to see what the next steps should have been for a company like Magnatone. When you consider that there were so many varied types of pop music in the sixties, all with different sounds, trying to reach out to all of them and say "try this amp" had to have been a tremendous task.
As far as public relations are concerned, its not a case that Estey missed the mark, and Ampeg and Fender did everything right. All amp manufacturers stuggled to keep up with changing times. What history now shows about successful amplifier manufacturers of that era is there was also a certain amount of "right place, right time" and luck that went into it. Sunn amplifiers is a good example with Buck Munger's Jimi Hendrix deal, and Ampeg's Rolling Stone endorsement was a similar lucky draw. Magnatone just happened to hit that endorsement lottery.
Also, Magnatone was small, and their resources were limited. Estey was no longer a west coast company, so it was unlikely that any of the rock musicians in LA or San Franscisco (the Doors, Byrds, Grateful Dead, etc) were going to latch on to Magnatone, or vise versa. The British Invasion acts were all overseas, and New York was more about session and club musicians (which Magnatone and Ampeg both tried to sell amps to) as apposed to a "pop music scene". So there wasn't, at the time, as easy place to point and say "that's where its at!".
Magnatone was exclusively a guitar and guitar amp company from the early days through the 1950's. With the rise of popularity of the accordion, Magnatone (Estey by the 1960s) began to push the accordion angle heavily, maybe moreso than the guitar amp angle.
By 1963, Magnatone had filled their sales catalogs with accordionists. Names like Antony Galla-Rini, Gloria Volpe, and Suzi Chandler were the headliners and closed back cabinets were fitted with 8" Oxfords instead of the open back 12" cabinets of the 1950's and early 1960's. It seems Estey was really inconsistent in this marketing because, oddly enough, despite the heavy handedness with the accordion angle, Estey hired guitarist Tony Jerome to be the national sales manager at about the same time!
Even the Magnatone's guitar player endorsements at the time aren't exactly household names nowadays (and its unlikely they were then!): Frank Marino (from the Jack Parr show!), and Arthur Smith were mentioned in the 1964 Custom Series brochure behind all the accordionists.
Estey went as far as to hire accordionist Henri Milano as west coast sales manager and then national sales manager as late as 1967! This is seems to be very contrary to the reshaping of the custom line in 1965 to be more guitar-centric than accordion-centric. Perhaps it is part to do with this misdirection that caused Magnatone sales to suffer.
As late as 1967, possibly after the M20's and other Customs were no longer in production, Estey was sending out press releases for young pop bands pictured with M20s. At least Estey was courting the rock scene.
(right) From late 1966, an M20 is pictured with a Starstream guitar. Text advertises both the Pro line and the Custom line. These two lines were sold concurrently for a brief time in late 1966 and early 1967.
(below) The first band looks like they were probably good for a Chuck Berry song or some Hollies jams. Promotional requirement: matching paisley outfits!
I found two Estey press releases with nuns pictured with Estey equipment. I'm not sure what angle they were working here but it wasn't anything to do with Woodstock or the British Invasion. The organ winning nuns at right were awarded this cheap import beginners organ in December 1966. Appearing in the same trade magazine was a similar picture of Vox giving amps and guitars to five guys with matching Rubber Soul bob hair cuts. Estey seemed way off the mark at this point.