.....So what you pay for then is build quality, FPS, and metering etc.
FYI, the last brand new Canon film SLR I bought was an EOS 3000 (as a second body with my 7e). The 3000 was bottom of the line with virtually no fetaures. It was around 1999/2000 and cost about $350. I bought it because it was so cheap - it was on special and was normally $500+. The top of the line Eos 1 was just over $2000 (and I think it still is). For the price, you get so much more camera today.
Just like today, 90% of people just bought the cheapest slr. Even now, I still run into people with 3000's.
In between the Eos 3000 and 1, you had the 300, 33, 30 and 3 - all differentiated by build quality, weather sealing, FPS, focus points, eye control focus, AI servo speed, encoding of data onto film rolls, electronic recording of shot data, flash synch speed, max shutter speed etc etc. By the late 1990's, camera had become very sophisticated and (ignoring the change to digital) its not surprising there hasn't be many big improvements to the basic features.
The prior generation used "5"'s instead of "3"'s in the model name. But like todays, there was never any real consistency with the numbering schemes. Eg, my first Eos in the early 1990's was 1000FN.