Two things old genetics take alot of time and commitment to keep going and breed them to be stable over time or representative of what their name implys vs the crossing of the week, and two the market sells and moves the most with the whole what “hot or new or with most hype”, so sure the old lines should be around but for retailers and “breeders” its just not economical.
Like old muscle cars or classics, there cool and awesome but how many people will go out to say buy one and maintain one with all their old tech and daily drive it summer and winter and in all conditions vs just having it as just that reminiscent collectible they use on select weekends.
Also something to be said that something in our minds past when looked at in fondness is almost always better than what it actually was.