Very impressed with my stylus upgrade.

Greater detail, soundstage, and much richer and textured bass.

To me this describes good analog vs digital.  I use an Ortofon Bronze myself and when I play a really good clean pressing like a BlueNote first pressing by Plastylite from the late 50s/early 60s it sounds much better than hi-res digital through my Auralic Vega.  Once I get into the Liberty years I give the Vega the nod over analog.  It's the texture and larger soundstage that I hear when analog is magical.  I know I need to upgrade my TT gear if I want to take it to the next level.

Is Ortofon using a marketing ploy in forcing a body upgrade as well when changing stylus?

Yes

At the the end isn’t the stylus the most important part of analog playback above all else?

If you’re using different styli on the same cartridge body then you will definitely prefer a better stylus profile, for example Elliptical is better than Conical, but a LineContact type is much better and much more accurate with information in the record grooves than Elliptical, Connical. Then we have MicroRidge, Fritz Gyger, Van Den Hul, S.A.S. profiles if you want less record wear, longest life-span of the diamond and maximum accuracy with the music in the record grooves.

Nude diamonds are better than Bonded diamonds
Lower tip moving mass is better than higher tip mass


And then we’re coming to different Cantilevers:
Titanium is better than Aluminum, Beryllium is better than Titanium, Sapphire or Ruby. Boron can be better than all of them. We also have gemstone (Diamond Cantilever) on some exotic cartridge.

also Hollow pipe cantilevers versus Solid Rod cantilevers ...

It's all about the stylus replacement of MM/MI carts, not about the cartridge generator as you can see