Very true. I'd have gone through fewer instruments if I had been able to try them out before purchasing them. Watching videos helps, but it's not a substitute for playing an instrument. Even strictly buying used, which I think is the best approach from a financial perspective, is not easy to do if you're outside of North America and are looking for something a bit more specific (or even if you are not specific). I returned an instrument to a dealer, because it just wasn't sure about it and it had been too expensive to keep, but that's not an option that I would be comfortable overusing (and it's still hassle).
What I do think is a better approach is to stick to a small number of fundamentally decent (good intonation, suitable action) ukuleles and learning to play (on) them well before going on a shopping spree. I didn't follow that advice myself and I paid for it by taking losses on every instrument I sold. In retrospect, I think I tried to "get it right" at a point in my ukulele journey where I wasn't skilled enough to really be able to know what I wanted. I knew I wanted something and was willing to pay for it, but I didn't know what it was that I wanted. The exposure to, and experience with, various ukuleles did help me refine my preferences, but it was all a little uncoordinated and aimless, fueled by this forum and the hype that surrounds some brands/etc. Being able to play well also helps with comparing instruments and pinpointing more accurately what the new ukulele should have that the present one doesn't offer.
Controversially, I feel that UAS is sometimes compensation for impatience and still developing skill.