Come on guys, it's a daft rule but it won't destroy cricket, and it won't affect the amateur game in the slightest. Previous rule changes (carbon handles/backs etc banned) have been banned from manufacture but not use in the amateur game, I'm sure there's still a few Ricky Pointing graphite Kahunas out there in club cricket for example. MCC have I think even already said that the same would apply in this case should the change go through. Plus let's be honest, lams are banned and it's not like you can't buy or use them.
Worst case scenario, all batmakers stop making big bats and we have to make do with 35mm edges. Last time I looked batting was about the batsman rather than the bat anyway (sacrilege!), and it's not like you couldn't still pick a bat you like. Most of my bats probably wouldn't quite make it through the new rules, but the one I own that definitely would is the best bat I've ever owned anyway! Life, and cricket bat marketing, will move on.