My frame is about 49 years old, and I've been riding it for 41. My Campagnolo Record hubs are still very smooth. I got a new Tange headset for $20-$30 a year ago. I can still get new chainrings for my TA Pro 5 vis cranks. My seatpost still meets today's standards, so I can buy new saddles. I can still get quill stems at almost any price, except that they start at a lower price than threadless and don't go up as high. Nitto makes Technomic stems, in fact, that will place the 'bars in a physically higher location to help my less flexible body, but they are not as pricey as the priciest threadless mast+stem available. Handlebars for my 25.4 mm stem are not in large supply, but I can get new ones for less than $40 ((though maybe it's today; I last looked a year ago). I just bought a hyperglide freewheel for under $20, including shipping.
I don't have the riding skills I had 40 years ago, but I don't have to shift much around here. Brifters are an advance, but they are incredibly ugly; I can get them if I want to go through the trouble of installing them.
C&V bikes look a lot better to me than many of the 'modern' bikes I see. Some of the modern bikes are uglier than anything ever produced in the C&V era.
I want to ride. The bike is primarily a tool. Decently-maintained C & V bikes work. That's enough.
It's one thing to prefer modern bikes over C&V. But if you think for a minute that a decent C&V bike can be anything but a great ride, you're doing yourself a disservice. There are lots of ways to skin animals, and there are lots of ways to enjoy a bike ride.