There is no comparison to an 87 Buick and a newer Vette. The reason you see a lot of older guys selling their Buicks and buying newer hot rods, for instance a Hellcat Redeye, is you get all of the goodie features plus 800hp on pump gas. You dont need to work on it, you put gas in it and go.
Buicks need work and maintenance if you can't work on them, you better have a good mechanic close by. The tech might be old but a 35 year old car will still mop the floor with most of the hot rods on the street. As for that tech argument, the turbos are so much better now, the ECMs do things they never did before, the heads make more power, the transmissions can be made reliable and the converters are so much better than they were 30 years ago. All are bolt on deals with a Buick or any other car.
I am one of those guys that want a killer in a straight line and in the corners. So I am in the middle of a Ridetech suspension, Baer brakes and 18 inch wheels and tires. I want my car to do both. And it won't cost me $100,000 or more to do it. I have more time than money, at least that is what I tell myself, and can do the work.
For me, I can sell all the Buick stuff and go buy a newer car with all of it ready to go. This all boils down the three things.
Age, time and money.