No, that is not at all a problem...
I have a spare belt in my car and the adjustment tool in the toolkit. I would have to be rather dumb to do anything else given your objections, no?
The biggest problem I face is the half inch of clearance between one of the pulley nose covers (a vanity item) and the back of my electric fan. Oh, BTW, with my setup I never lose power to a belt driven fan... so cooling will never be an issue from that regard.
I will agree with your second line of reasoning while adding that I would much prefer to look under the hood, confirm that the Serp belt has many years left on it and go driving rather than the far more frequent "oops, better change my belt" that will inevitably happen far more often with V-Belts. Or worse, spotting that damned belt that flipped... In fact, given the amount of driving I do, this belt should last me many years before I need to deal with it again from a replacement standpoint.
That said, if you have never owned a modern car then you are really doing yourself a dis-service. As much as I love my Toronado - and believe me, I do as you should well understand - the new cars are just phenomenal. Amazing performance, fantastic quality, superb craftsmanship, great looks, interiors that they could not even dream about back in the day and so much more. You really have no idea what you are missing. Both have their values, and to write off new cars in my opinion simply robs you of a very good experience.
The Modern Cadillacs, the Camaro, the new Voodoo engine in the Mustang, any high performance Eurocar, the Hellcat, on and on. The number of fantastic cars I never dreamed would exist back when I was a kid is legion. You really should go drive some of the better ones just to have the experience even if you are not going to buy.
I drove the Jaguar XF and the Cadillac ATS-V back to back and they were both amazing in different ways. The Jag was refined, smooth, powerful, luxurious and more all while driving superbly. The Cadillac was not as refined, smooth or luxurious but it had a 6-speed manual and that sweet twin-turbo V6 putting out 464 HP with an intensity that is hard to find in classic cars unless you heavily modify them. And the handling! Nothing built back then can match without massive upgrades.
If you are dismissing new cars out of hand then you are just losing out on some wonderful machines. I am not suggesting you run out and buy one - although you may find you do if you take my advice, they are that good. Don't sell yourself short!
You are, of course, welcome to choose as you will. However, I have the same choice, and irrespective of your opinion to the contrary I am far happier with my Serp setup than I ever was with that crappy old nasty looking V-belt setup that never worked well for me.
What is so wonderful about this hobby is that I can think you crazy while you are out there enjoying every minute of your time with your hot rod while I am out there enjoying every minute of the car you think I am nuts to be in! To each his own, and that is how it should be!