The folks who suffer from an embarrassing surplus of avios are generally those who get them through work. It's not a long-term problem because it builds up a pension pot of miles which you can live off in retirement providing you have lifetime Gold, which would normally come along with zillions of Avios.

Self-funding leisure fliers need a strategy to balance earning and spending avios. Like OP I also buy revenue tix to maintain status but I work on a 2-year cycle. Year 1, spend just enough cash to make 1500 TPs. Year 2, as GCH, fly exclusively on avios, saving my cash and earning no TPs. Year 3 (=year 1 of new cycle) I have Silver from the soft landing and start spending again. This keeps the avios more or less in balance and ensures I don't drop below Silver. That's the theory at any rate. Where it breaks down is the increasing scarcity of reward seats on the routes I mostly fly.