GAS has afflicted me throughout my photographic career. A decade ago I had a major clear-out, and I let most of my systems go -- LF, MF, 35mm. I kept an EOS 5D MK II I had just purchased, plus the "essential" EOS lenses for it. For 9 years now, GAS has not bothered me (though in truth, I've done far too little photography -- been too busy with work).
Now I've gone part-time, and have time for this wonderful hobby again. In the past 3 months, I've bought an X-T2, and two extra lenses for my EOS 5Dii. Lot's of accessories (to aid with video work, mostly) keep arriving from Wex and Amazon. I think I can safely say that I have GAS again. Fortunately, it does no-one else any harm...