I don't think getting rid of the two signature rule caused the decline in membership, that is demographics at work and changing tastes likely. I don't think the idea was to keep this an 'elite' club like a country club, the reason as I was told is because of the selling/buying of items through TCA between members, they were afraid of unscrupulous ppl joining and selling or buying stuff and stiffing someone else. Given the nature of it as a collecting organization, it was a way to have a mechanism to make sure the person was authentic. The downside was, from personal experience, some did see it as a way to keep it a small group of cronies, especially at the local group level. The crowd that hung out at the local hobby shop were kind of the gatekeepers from what I could tell and some of them seemed treat TCA like a country club.
From what I know, that 2 signature rule extended to York as well. The member halls were designed for member to member transactions from what I was told (met a guy who gave me a non truncated history of York *lol*) so again it was making sure you didn't have unscrupulous ppl joining to rip ppl off. These days the member halls are really just vendor halls anyway, they may belong to TCA, but it seemed obvious these were dealers mostly, not TCA members selling off their personal collections (as the person I was chatting to put it, guys buy out estates for pennies on the dollar and attempt to sell it at ridiculous prices, though in more colorful language).
Given how much the world changed since TCA was founded, dropping the signatures made sense. Lot of people live in areas where there aren't places to meet TCA members, and given that today the world is increasingly virtual, just didn't make sense. With transactions going through the TCA website, it is a lot easier to prevent scams, ban people than the old mail based transactions.
And honestly TCA is still doing its job. I enjoyed York and if circumstances allow it, I will be going regularly, and I have started going to local events where time allowed. Nice to see there are still people with enthusiasm to run things like TCA and York. I am sure some wish for the old days where it was a close knit community, I understand that, I grumble enough about other things that 'aren't the same' (comes with age and my expanding waistline), but I think they did the right thing. There are things I think TCA should do looking to the future,especially around the website and the like, but I'll communicate that to them as suggestions