Well as always, each to their own.
I am invested in so many authors, and regularly have huge breaks anyway, that are mostly my fault ... or the fault of life.
I like George's writing, so I can wait if I have to, and I should still be able to enjoy the belated books if they ever come out.
I usually try to hold out and not start reading a series until I have all parts, but often easier said than done. I did that with Terry Goodkind, got all his books without reading more than a few paragraphs, just took it on faith I had good judgment. I wasn't let down.
I've sometimes thought a series was either finished or close. Made that mistake with both Robert Jordan (6 books in) and George Martin. With George though, I kind of felt under pressure, as many I knew were watching the TV series, and I was keen to hop on board .... but only after reading all the novels ... now on hold indefinitely, awaiting the final books.
P.S. Whether I wish it or not, I now also feel some animosity toward the TV series. Time they say, heals all wounds. Ha ha ha ha.