I remember there being such tentativeness when CGC first came around. And there were A LOT of dealers who were saying "this will never work, it will never last."
I don't even remember when I bought my first slab, but I do remember, from the period of about 2000-2005 or so, that it was a fluke, an anomaly, to see things slabbed at a convention, never mind a store. There would have been a couple hundred slabs on eBay in total.
I mentioned a Showcase New England eBay sale a couple days ago, which included every Marvel SA key. This was in mid 2001. I have the results somewhere, I'll scan then if I run across them.
There were a handful of slabs...but only a handful. AF #15 was one. The FF #1 was NOT slabbed.
I cannot imagine such a sale now taking place that would include ANY raw copies of those keys.