You make a good point, though I’m not as certatin as you that feathers would fossilize. Impressions of the feathers have been found, however.
Keratin, the substance that makes up feathers, fingernails and hair, seems to fossilize if it is sizable. Neither feathers or hair are ‘chunky’ like the claws of large dinosaurs which do fossilize.
Also, and this is germaine to your position, dinosaurs died out a long, long time ago. The amount of fossilized remains is actually quite limited; in fact, a ‘complete’ fossilized skeleton of a T-rex has never been found - something is always missing! Thus finding fossilized feathers may be impossible due to the fagility of the item and the length of time that has passed.
Maybe we will never know for sure.
But I know they have found fossilized flowers, so I would think a feather would be quite possible.