Im not sure about that. How many mechanics in the world are there ? A lot. So even if a small percentage have internet and are willing to try new stuff it could well be a market that is worth tens or hundreds of millions. Maybe.

How many mechanics have email ? I think a large percentage.

How many people starting up new mechanic businesses are in their 30s or even 20s and reasonably net savvy ? I imagine quite a few.

Course these questions are best answered with some research and discussion with mechanics.