I wouldn't stop, but I wouldn't back collect either; I would just keep collecting the way I've always done since 1984; by buying current stuff. Even if I could afford to re-purchase the toys that I lost, the fact of the matter is that they would never be MY toys. IMHO back-collecting a lost collection would be futile because the new toys simply would not be the toys that I grew up with. They wouldn't be part of my childhood. Even toys that I've collected in adulthood still represent different stages of my life, e.g. 9 years ago I was burgled and some of my TFs were stolen, including my original G1 Optimus Prime. Someone generously gave me a free 1984 G1 Optimus Prime, which I am forever grateful for, but ultimately that toy will never hold the same personal value for me as the toy that I've lost. It's actually in physically better condition than the toy that was stolen, but the stolen toy was the one that I grew up with. It was the Optimus Prime of my childhood. When I get reissues, I actually still hang onto my original G1s, no matter how worn and damaged they may be. The reissues are the toys that I will play with now, but I keep the originals because they are ambassadors of my childhood. No reissue can ever replace that.

So considering that what I would lose would really be irreplacable, I wouldn't bother back-collecting. I'd most likely continue collecting current and future stuff, but I wouldn't hunt down old toys from the aftermarket.