The main cause of teeth yellowing in older people is age and this as you say Wyllow caused by thinning of enamel, and the dentin (interior) of teeth showing through. If you inherit good teeth from your parents (ha ha not false ones) you may be lucky and your teeth may not discolour much.
The last thing I would use on my already thinning enamel is abrasive “whitening” toothpastes, or bleaching, even done professionally at the dentist. I don’t want the enamel to be further weakened. It’s a good money earner for dentists I imagine.
I visit a hygienist regularly, and I guess if my teeth become badly discoloured would consider veneers, at least at the front.