From experience: 

The issue with all vehicles as they age is parts availability. There is so little money in selling parts any more there is little incentive to make them in small shops. Starting around 2021 OEMs started dropping support new part for most vehicles older than about 8 years, or when extended warranty expires. We were returning like 35-40% of the OEM parts in our shop sourced from well known wholesale OEM resellers (we were one of the few with good connections in Canada where most of our parts are manufactured these days) because they're so poorly manufactured now. Remanned parts have a huge return rate too. Resellers can make money on them so there will be fewer places to purchase parts also and thin margins for companies like RockAuto and CarId means they'll cut support just as easily.  For precision powertrain parts, most are mfg by Bosch, they raised their minimum purchase quantity such that warehouses have to purchase like $10,000,000 of product at a time which caused us massive order hold times. The OEM parts scene is a huge mess.

Anything older than 2000 I suggest hiding away least 1 parts vehicle on your property you can scavenge parts from as your vehicle ages. 

Something to consider, in 2023 SEMA released their docs for something like $150m in revenue for the entire aftermarket parts industry THAT'S IT. I'd be willing to bet Holley accounts for 100+ of it.