That is a valid point, but to be fair, for the cost of something like the M-Scaler, just as an example, I could purchase so many of these "well-measuring" devices that even if they failed at a rate of every year, it would still be less expensive to just constantly replace a "well-measuring" affordable DAC which is audibly transparent for all human beings ever born. Not to mention, there is no evidence that these "well-measuring" devices fail chronically.
I take your point that great customer service is very important, and it certainly is laudable, but you seem to be implying that the more affordable devices (by which again I sense you are talking about the many excellent products from Chinese audio companies) are going to fail at a high rate. Again, I do not know that this is true. My experience with quite a few devices from FiiO, SMSL and Gustard, for example, have been very positive without a single failure yet, years into ownership for some of these very affordable, and well-measuring devices.
May I also point out that when companies are able to provide such incredible service that in a capitalist system of business, that almost certainly indicates that the profit margins are high enough that they can do so. While it is wonderful that they do, it is extremely unlikely that this service is being funded out of the companies operating coffers. Put bluntly, there is plenty of profit and it enables them to do so because having high-spending customers who are happy with you is like a license to print money. They know darn well that the typical profile will be people who earn great money and they will be repeat clients. That is fine, I'm not judging that business model, we all make our choices.
The other more affordable business model is such that sure I may not get the support as you are discussing here, but I also don't need to sink a massive cash outlay into a device either. I can purchase a "well-measuring" audibly transparent DAC for say $250 that might actually last for many years. If it does fail in say 2 years, from an environmental perspective that is unfortunate, but from a financial perspective I am way, way, way ahead as compared to having to spend $4000 on a product. So really, both business models have pros and cons and it is a fallacy to assume that one is clearly better than the other. It depends on the user.