They weren't full time in the 1980's, either.
Seek out these guys if you can. It's well worth rearranging your schedule to fly with them.
I would rearrange anything to!
Unless I've misunderstood the EASA, and other, changes, is it not so that ALL instructors must now be under the wing of an ATO or other such beast and that these fabulous assets to aviation would have to kow-tow to the policies of such 'schools' and are therefore potentially doomed to the sidelines?
They've essentially had their wings clipped so there will fewer available as standalone instructors without going/having gone down the route of registering as an ATO etc. with all the (relative) hassle/cost that has created.
How, then, would you legally be able to use their experience and log it?
Would love to know the prevalence/incidence/consequences of these developments.