The Corona uses a lot of off-the-shelf parts. Meaning they were not designed specifically for the Corona (code ST171?). A lot of those parts are still in use today by newer Toyota products including the Camry, RAV4, Fortuner, etc. You'll find bits of the Corona in 'em.

Btw, product support usually extends 15 years from the end of production. At least that's how it goes in other markets where product support is mandated by law.