“How about cast iron frying pans?”
They have particular heat distribution properties that many find desirable yet are impossible to reproduce. As one who has both non-stick and cast iron in their kitchen, that particular example is like saying that we no longer need strawberry ice cream because we have chocolate ice cream.
“Shouldn’t analog alarm clocks be gone from the face of the earth since everything just about has digital?”
They kind of have, actually. True clockwork is hard to find, with many analog clocks nowadays being quartz movements driven by a battery instead of a spring. However, there are enough people that like the aesthetics of analog clocks that it’s still viable to make them… or at least make a clock app for your phone that looks like one.
The point you seem to be missing here is what it actually means to be obsolete. Obsolete doesn’t just mean that there is something better out there. Obsolete means that demand for something has fallen off to the point where it’s no longer commercially viable. That is why cast iron cookware and analog clocks are still on the market while VHS and floppy disks are not; demand.
In most cases, the decline in demand is due to technology introducing something superior, or at least innovative in a desirable manner while still being affordable. That is why modern cars are fuel injected instead of carburated, and why MP3 replaced cassettes for portable music. But sometimes technological advancement is not enough to make something obsolete. Blu-ray is technically superior to DVD, but is not yet cost-competitive enough to fully replace it, therefore DVD is not obsolete; there are enough people with DVD players that haven’t upgraded to Blu-ray that ther eis still plenty of demand for DVD.