I'll say it...I think it started with Tyree LE frags...
Everything costs more nowadays due to designer names and such. People find a nice color, slap a cool name on it (which apparently every single coral vendor does now), and suddenly it's a $200/0.5" frag. Gone are the days of "blue tipped green stag" @ $20, they have been replaced by the days of "super apple slimer lime in the sky dragon claw stag" @ $150.
Most of the newer reefers pack their tanks full of frags cause they're small and there would otherwise be large expanses of rock, and leave no room to grow. Three inches has turned into a "colony" when as said above, is what a normal frag used to be. When I started keeping SPS 15-20 years ago, you could buy a beautiful teal/purple tenuis 5" colony for $50 bucks...more like $500 now.
I personally love to go to the bargain bin and take chances on cheap SPS and see how they color up and grow. If they stay brown, 10 bucks down the drain, if they color up...maybe name it "kalare's radiant purple hairy bigfoot milli" at a bargain $80/.25" frag!