One interesting observation btw.
Before i bought my boat (Rawson 30, 1971, 10k$) I talked with many people for advice and one advice seemed to be universal: Don't buy a catalina, hunter or beneteau. Really everyone told me this, both online, in quatemala and in florida. Everyone seemed to agree that these are weakbuild pieces of ****. I bought the Rawson partly because it has a very good reputation for being a sturdy blue water boat.
Now each time i look at treaths where people talk about buying boats for 100k or 200k, i keep seeing exactly those 3 names returning.
TBH, that makes me thing that people with the money for a new boat seem to be less informed, go for the well advertised nice looking picture boats and just look down upon old boats because they are cheap
I suppose that is why the VAST majority of the above mentioned pieces of $hit are still being sailed even though they are 40 years old? If all you are planning on doing is coastal sailing (going no farther than say the islands on the east coast or the California Baha path) then buying a blue water capable boat is really a waste of money and time, as you will spend twice as long getting to your destinations. Maintenance costs will likely be more because of more limited production means more custom parts. The mentioned turds would not be in Guatemala if they could not get there would they? Now a poorly maintained "blue water" boat is going to be just as bad as a poorly maintained production boat.
Another issue is going to be ability to sail. Say the Chesapeake you are going to be motoring a lot in your slow Rawson, while the Catalina/Hunters/Beneteau's will be sailing past you enjoying the peaceful sail.
My real guess is that the person giving you that advice was trying to sell a Rawson, not a Catalina. This may have tainted there view.
But in general yes a 70's boat is likely to need some updating. But keep in mind electronics are considered outdated in just a few years, so even a 2000 boat my need new chart plotters and radar if you need such stuff.
So the real lesson is get a boat that best serves your needs. If you are planning on real blue water adventures then Blue water ability is good, it is a disadvantage otherwise. "less informed" absolutely not, different priority's yes, but likely better informed based on your post.
Just like the miss-informed thought that they built them better because they did not know how strong fiberglass was. No they were over built because they did not yet have the techniques to do it any other way. Just like people look at cars the same way, saying they were more reliable back in the day, untill you look at real statistics and today's cars are more reliable, faster safer, better handling and get better gas mileage. Now I love old British sports cars, but no way do they compare to today's cars, except on a windy country road on a sunny Sunday. (if it decides to start of course) You sure don't want to try to get to work in one, believe me I tried it!