Dell has got to be one of the most frustrating companies that put out a linux laptop. They put out a laptop certified for ubuntu but then never support newer releases. A big part of their hardware is always proprietary drivers like webcam, fingerprint reader etc… Then you update to a new LTS release because lets be serious 20.04 at this point is going to sunset in a couple of years… However after you update the webcam stops working, or some other hardware stops working. Then you are constantly troubleshooting to get it working and every kernel update it breaks again. If you ever did ask support they will just tell you to go back to 20.04 image from dell. Not to mention all their OS tools are made for windows even the ones for making linux recovery images… like WTF! I am two years in on this laptop and I am just getting rid of it I cannot put up with this nonsense anymore from them.
You have this view because your hardware is from an era where fingerprint reader largely weren’t a thing and webcams were connected via internal usb. The issue is not that the Linux kernel drops anything (between you and op, you’re the one with the old hardware). The issue is, that fingerprint readers became a commodity without ever gaining universal driver support, and shengians like Intel pushing its stupid IPU6 webcam stuff without paving the way upstream beforehand
In that case, the solution is to buy hardware that is linux-certified.
So not Dell, apparently. OP has a valid point. Dell claims to support Linux but in practice doesn’t.
Specifically the shitty IPU6 situation is on Intel, and is invariant to any laptop manufacturers. I also have a Thinkpad X1 with that issue. So for that the situation that one manufacturer would support it properly (i.e. upstream) and others don’t can’t exist, as soon as anybody puts it upstream it works for everybody. Thankfully there’s some progress (search for libcamera) and in the not too distant future it should work ootb. For fingerprint readers it is a different story though, as there are many different ones, so that one is on Dell indeed