Not sure why this morphed to restoration, rather than trees?
I would have to look back at some of my 1980's master plan reports. I think I warned about "over planting" and even recommended some tree removals, but mostly to break up straight line plantings, and promote possible heroic escapes from under trees. But, I recall a few calling for "native areas" and turf reductions, which I think led to some tree removals. That said, it was always an uphill battle.
And, I recall a few master plans where the original call was about some tree or another that some wanted out (because it blocked their shots somehow) and some wanted retained. Sort of OT, but I lost a job to C and C in the early 1990's. The club's one request was to save the tree by the 4th green, even though its shade and roots were killing the green. I glibly said I would save it, as long as they told me where to stack the logs.......wasn't the right answer.
IMHO, it always needed a famous course doing it to highlight the trend, such as the US Open of 1992 (?) at Pebble Beach, where the USGA promoted fw chipping areas over all deep rough. Or the 1974 PGA at Inverness, which widely promoted restoration of Ross courses from its original roots in New England.
For tree removals, it was probably the US Open at Oakmont in 2008, but it seems like the movement had been going on a while, and that just made it okay and actually accelerated or mainstreamed it.
I would still say that there are counter trends for every trend when it comes to tree removals.
I would also say that it made perfect sense to plant and plant a lot on those Midwest courses built on cornfields, but you can have too much of a good thing. Those probably weren't done by gca's, but after opening by the committee.