I have owned a number of boats--and bought 4 new (including a Tom Cat). The other 20+ have been used. (OK we built a few boats along the way also). Every one of my new boats had some serious problems. I still see some issues in new C Dorys. The case of my Tom Cat, It was about 200 miles to the dealer, and I knew I could fix the issues better than the dealer could. The only time I called on the dealer for quick help--was when the hydraulic steering failed --about the second time out. The dealer did one of their mechanics to power bleed and help install the new helm unit which Teleflex had overnight expressed. (I had to arrange that). There I bought new, because there were no used, I wanted specific upgrades--and did not get them. But that was over 10 years ago, Different owners now, and I believe better.
I have also purchased one C Dory with known abuse and serious issues--but it was purchased at half the value of the boat. I did it as a project, and it was a good boat, and wise financial decision.
The point about newer motors is valid. But most motors after 2007 are injected, so injection is not an issue. Same with larger alternators. Look at the hours on the engines. Although some in commercial use, get up to 10,000 hours, on outboard motors, but in the average use of a C Dory, one would strongly consider replacing motors over 2500 hours..
Electronics--Ssobol is spot on. The older ones are still good if they work--but the newest latest greatest, do have some really great features. My son's boat has a JRC Radar 20 years old--and it works very well. On the other hand, we bought him a new depth sounder/chart plotter, with better charts, and down scan/side scan for the fish finder.
Also consider what you want in a boat. I like the plain interior, where I can turn the hose on it, scrub it out if necessary. I have seen too many headliners which sag and get mold behind. But since I live in Fl. that is a greater problem that in the PNW.
My current C Dory was in excellent condition, engine low hours, minimal electronics, and for me as good, or better than a new boat. Only down, was that the engine was not injected, and had a smaller alternator, than the newer boats. Not worth the $10 to 12K to re-power.
As most have said--only you can determine if you can "Afford" a new boat. How you manage your finances is very personal. As one who has been retired over 25 years, I observe that many folks do not save enough for a really comfortable retirement, and don't understand the uncertainty and costs of aging.