Except that the cheapest Galaxy S20 at $999 is barely even a fair fight vs the most expensive iPhone 11 (the pro max) which cost a minimum of $1250 unless you're happy with a $1000+ phone with 64gb of storage.
The still extremely premium S10+ at what is a price point of $800 directly competes with the 11 pro max, $400 cheaper and will likely still stack up very well vs the non pro iPhone 12 for what will be a lot less money by that time. The iPhone 11 non premium phone still goes for $650. Or $750 if you want more than 64gb of storage.
If you're talking value vs iphones, it's still there in droves if you're looking for it.
Except average people don't look at phones that way. They generally look at the price tag and go "oh, x is cheaper than y", even if the S10+ went down in price, you don't always see people flocking to them due to wanting the newer model (case in point, XR vs. iPhone 11 - even if it's nearly identical in build, people flocked to the 11 because of the perception of being a base model vs. perception of being last year's model/budget version).
It's still a pretty big ask to go from under 1000 to basically 1000 as the baseline, and then paying more depending on what extra features they want. The enthusiasts will buy the highest possible configurations of the S20 no matter what, but the idea of paying more for phones is something we've seen people resist (it's why Apple cut the price of the 11 in the first place, this just seems like a more extreme variant of the premium pricing that iPhone X, XS, and XS Max got in 2017).