I do understand where the OP is coming from in a way.
It's about relevancy. I move around constantly with the military so new groups are always forming. Normally with the current edition. So when the masses move forward, so do I.
Yes, I could use my BECMI, my 1st, 2nd, 3rd, and 4th books, because no one will ever take them away from me.
But as time passes I feel distanced from the "current" phase of players. I begin to not understand the terms, or I miss the new concepts that I can incorporate into my game.
I don't want to be an island, or a backwater, slowly growing stagnant or out of touch.
Now, having said all that, "IF" I had a stable group instead of six or seven groups over the last 26 years, it would be a lot easier to stay with and play whatever version we liked forever.
I am retiring, I am done with the military so maybe that option will be open to me soon.
But I will always be interested in staying relevant.