You think $50 will make a difference for Samsung, though? Or for customers, I should say? I think if given an S21 and an iPhone 12, people would pay $100 more for the iPhone. Not everyone, but just Average Joes that are due for an upgrade, I think the Apple brand carries more weight, at least in the US. Samsung is going to have to undercut a comparable iPhone by $150 or more, or people will just pay more for the iPhone to keep up appearances.
I think at this point there aren't as many people moving between iOS and Android, as none of them have killer features big enough to make it worth the hassle at this point - they're more similar than they ever were. I noticed that over the last two or three years ever since Apple added things that Android phones only had and Android became as user-friendly and "just working" out of the box the way iOS was people are sticking to the ecosystem that they're invested in.
Even for me, it would be painful to drop not only Android where I paid for most of my apps, but also Samsung as I'm quite invested in their value adds. I use Samsung Pay, the Galaxy Buds which I really like (which work best with Samsung phones) and am used to and like their UI and the added functionality of their skins.
I think Pay and the Buds are genuinely better than what Apple has. Even if their Airpods objectively aren't necessarily worse, just different, Apple Pay just isn't as good and they'd require me to make a lot of changes and some additional purchases to try to match what I already have and like with Samsung. Recreating the same experience with an iPhone would take a lot of time, money and in some cases I wouldn't be able to fill all the gaps.
So I think Samsung is mostly about attracting upgraders from within the Android ecosystem, they just need a new appealing phone at a good enough price to attract people, and slashing prices even by $50 sends a message that it's a better deal than the S20 was at least, especially if the S21 (or S30, depending on what they end up calling it) is a better phone all-around. If they ditch the charger and headphones, there is a great opportunity to slash prices even further though, which would be great for them. I already have 4 fast chargers at home that I don't even use and two pairs of their AKG headphones that I got with the S8 and S10, of which I only use one since they're good for Zoom calls. After upgrading to a phone without a headphone jack I don't imagine ever using them anymore anyway.
Their fast charger and the AKG headphones aren't exactly cheap - together they easily account for at least an additional $50 on their end. If they don't transfer all those huge savings onto its customers, Samsung will further bleed users - that said between the above and savings on parts they have a shot to bring back some excitement precisely by slashing prices on the S21 at launch. Otherwise it'll be another good phone to buy only after the S22 (or whatever they call it) launches.
As for 5G, the biggest factor that doesn't make it exciting for me is how good 4G/LTE is. Not only the speeds, but the infrastructure investments and modem improvements making it as dense and trouble-free as it is today. 5G will take a long time to reach the same level of maturity, and it doesn't offer enough in terms of needed improvements to me as a user want to jump to it in the sorry state it's still in. You can actually say that it's the best time to use a 4G phone as the infrastructure is very mature and the speeds are more than almost anyone would need on their phones. As a matter of fact, the biggest difference you would notice with 5G as a user is how often you're dropped to a lower standard compared to a solid and stable LTE you get pretty much anywhere there's any radio signal. Since I wouldn't even tell the speed improvement that 5G provides while on it (unless you stream 8K video on your phone or something) at the moment I see 5G as a net negative.
To be honest 5G is mainly appealing to the carriers as it allows for more users to be serviced with less/cheaper equipment, not so much to the end users at the moment. Phone manufacturers are also happy as they have a larger number on their spec sheet to try to bait people into paying for. It will be more appealing to the end users only once the infrastructure matures and 5G inevitably means more and cheaper data, which isn't the case at the moment as we're still essentially paying extra to cover the big deployment expenses, and we're not getting the final product worth paying for yet.