Even for those of us who do wear suits on nearly an everyday basis, the problem with extremely high quality suits isn't that they make us look like trust fund kids (an utterly meaningless criticism, in this context), but that very high quality suits are often made of fabrics which are arguably less durable than their more moderate quality alternatives. A 150 fabric might be nicer than a 110, but if the 110 is "harder wearing," it may be the better choice for a suit that will be worn frequently. But such considerations are irrelevant to your situation, where the suits will be worn infrequently.
2. Bear in mind that most suits are abandoned in less than many years not because they were of insufficiently high quality, but because most men are unable to maintain the same size body for many years. Few men have precisely the same measurements at age 30 as they did when they were 18. Fewer still have the same body at at 58 as they did at 33. Yes, a few do. But not many. Because even if you watch your weight and try to exercise regularly, our bodies do change over time.
So, while it's perfectly fine to want a suit that you hope will last you many years, don't simply assume that it will.
And, of course, those 4 bespoke shirts you're talking about aren't likely to last for many years, either.
3. If you really want suits that you can wear for many years, consider that some styles are far more ephemeral than others. Currently, slim fitting, highly fitted suits are fashionable, at least in some circles. Buy a couple of such suits today, and even if they fit you perfectly in a dozen years, will you want to wear them? Maybe not. In 1976, leisure suits were all the rage. Far less than a dozen years later, you wouldn't want to have been caught dead wearing a leisure suit. An extreme example, I grant you, but the principle is valid - if you want a suit you can wear for many years, eschew all but the more timeless (which for men's suits are often the more conservative and traditional) styles. And consider that even those styles do evolve over time.
4. I note that you're in Princeton, NJ. That's only about an hour's travel time from NYC. If you really want a couple of MTM suits and shirts, you might want to consider going into NYC, where there are likely to be far more expert tailors able to meet your needs, likely in a greater range of styles and price ranges.