I feel you on the lack of SD but shortly after having this same thought I looked at my actual usage and noticed that I'm only using about half of my storage now. I was actually a little shocked because I seem to have more apps than everyone I know, not counting the preinstalled stuff that comes on the device and with Samsung that seems to be a lot even with an unlocked device. So for me the turn-offs for the S21 were Size, lack of SD and way off in the distance lack of a headphone jack. The headphone jack wasn't really that important to me, it just ticked a box of missing things. The size was a concern, ticking a bigger box for me. I went from the S10 to S20 and I really noticed that size difference in my everyday carry. It no longer fit neatly into my pocket. I found it binding, hitting and being in the way where my S10 never was, so imagining getting an even bigger device didn't put me at ease. The lack of SD as I explained before was kind of a big deal until I looked at just how much space I was actually using. It actually may end up being a bigger deal than previously expected in the coming months as I use Google Photos to back up most of my pics and things and they've just announced that they're capping it so they can start to charge for storage. Around this same time Samsung announced their cloud storage option, which also quickly becomes a paid service, so the SD while I wouldn't need it today seems like something I would need tomorrow. The deal breaker for me was the removal of the magnetic strip pay tech from the device. Samsung has long been known for its Samsung Pay feature and a large part of that was how well it worked and a big reason for how well it worked was due to the fact that it worked with old-school card readers even if they weren't equipped with NFC. Granted more and more places are updating and like so many other things the tech becomes standard. Eventually. But we're not at eventually yet and it would be nice to still have that tech until eventually is now.
As for your question on the price it has dropped some but since the release of the FE model I'd say you'll have a wait before either price falls too much more than they are currently. You might find a deal or a sale at a third party retailer but not likely one direct from Samsung for a while longer now. I've also heard rumor of an S21 FE. Not sure how true that is but if they do the same thing with it, that would be when you might see a drop in the S20 line.
Best wishes