Daveyf,
The styluses have different configuration. Conical stylus has one face. The sophisticated Shibata or Micro Ridge like have up to 32 faces. To mount and align such on a cantilever takes laser beam technology to get the angles right. When using, any mis- guidance or mis-aligning damages the original shape quite fast and easy. All styluses diamonds are lab created and polished these days. Also, some cheap styluses were made of ruby/sapphire like composite or different corundum composites. Sometimes they were good for just 100-200 hours.
You are more than welcome to believe in long life of damphers because you have experience and hear it right. We test these with proper devises, have results and I stand behind my words.