From my uderstanding, bespoke products have always been expensive.
Years ago I read up on Rolls Royce automobiles, and one of the questions brought up in the book was about why a Rolls Royce was so expensive. The answer stated how the cars were built one at a time from quality materials, and the time it took to make them.
I guess you could think of bespoke suits as a Rolls Royce. (The older ones, not the newer ones

)
Also, prices have change with time.
In other words back in 1958/59 when Cary Grant stared in North by Northwest I believe his paycheck was $100,000. In today's market it might be more like $100,000,000.
In an old GQ from the early 1960s that I have there is an ad for Oxxford Clothes at Neiman Marcus's men's epartment, the cost for an Oxxford was around $245.00 compare to the $3,000 plus today. $245.00 was a big chunk of money for a suit in the early 60s.
In the 1968 movie "The Thomas Crown Affair" the suit cost around $350.00.
An Anderson & Sheppard bespoke suit around 1980 was about $1,500, that is stated from Alan Flusser's 1st book "Making the Man."
Flusser also has stated in his books that men's clothing has gone up dramatically over the years.
Best Regards,
Cufflink79