With the experiences I had owning a vintage shop and managing a repair bench with two luthiers on it, I can tell you there is no single answer that is right for your question. However, it is true that when you put a new finish on a guitar it will take a long time for the wood to adjust to it and start singing again. In some cases, I have seen guitars that essentially needed the refin to hold them together -- old brittle woods needed the support, and a 1934 00 Martin comes to mind. The key is to do the refin with the same ingredients as the original finish and in the same manner. It still sounds new, but if properly done most players care little about it.
It is definitely true that "collectors" get very upset about refinishing. It isn't a matter of tone, really, it is more a matter that the buyer wants to get proper value for their money when buying what is supposed to be a rare, vintage instrument. There are many D-18s and D-28s around from the 50's and 60's, for example, but there are very few in near mint condition. Understand that the collector is not buying the guitar to play it - they are likely buying it to display it. Most collectors have at least ten guitars. You simply can't expect them to do much with ten guitars other than display them. When I still had a collection, I held a jam session at my house every Sunday and people came from far and wide to attend it - admission, a pack of John Pearse strings (which I could sell you if you arrived empty handed - lol). I had 32 guitars and I could at least rely on most of them getting played each week.
The real tragedy of collecting is inactive wood. If you take a singing guitar and lock it up in a case for decades they can take years to wake up again. Refinishing a guitar so it can better be played or enjoyed is much less a sin than locking a guitar up in a cabinet. If I had to choose one camp to destroy, it would be the collector camp, not the refinishing camp.
I once had an electric guitar that was naturally broken in by years of road wear. It sounded good but looked like Hell. I had it refinished properly, using original techniques and products, but opted for a rarer colour than the original. Indeed, it cost me around $1500 in value loss to refinish the guitar ('62 stratocaster from white to blue) but once it was the nice colour and all done up proud I played it every day. Playing it is what mattered in the end and the current owner plays it on gigs night after night to make his living.