This is a pretty classic question and one for which "to each his own" is the most apt answer I suppose.
My perspective: Simply put, quality and simplicity of design and materials are timeless if the caretaker holds up his end of the deal. Care is likely more about discipline than money though plenty of both are involved.
While I do not hold credentials as a long time big boater, I have owned and operated significant fleets of equipment on land and my experience there has been reflected on water so far and is also reflected in my choice of the two large boats I have purchased. Robust quality of build materials and design in the original build stands the test of time and use consistently. I run some very modern, very complex, and very expensive equipment with lots of electronics and no linkages and it is fun to run and impressive when it does. Often, it is not as long on reliability and longevity as some of the late 70s and eighties Caterpillar construction equipment that has logged over 25000 hours in some cases with original frame, block, and much of the auxiliaries.
With the way that the vast majority of us boat, I think there is almost no risk of "using up" a high quality boat if we take decent care of it no matter how old it is. Some of the modern marvels, perhaps not so much in my view. Though I may not feel that good about it, I expect I could "afford" either.
I expect both of the thirty year old boats that I own to outlive what remains of my boating years and though I won't give a care about it when my body temperature makes its final descent, my guess is they will still be worth what they are now if I do my part in the meantime. Some parts of boats are 'consumable'. That is as true of new boats as it is of old boats. The more of this 'stuff' that you have, the more you need to work on or replace. You may get a honeymoon with a new boat but the consumption is still occurring and the hourly or daily cost is the same.
