Many people, such as me, have already dropped. I often managed to get Silver but I'm now Bronze. They could renew that for ever, but I don't value any of the Bronze benefits (with my pattern of flying) so it doesn't encourage me to fly more.

In fact, apart from not flying CE any more (as tier points hold no value for me now that I can never get enough for Silver), the abrupt change from BAEC to BAC opened my eyes to the fact that Avios are also things BA can, and do, play around with. I no longer wish to hang on to any, so am using them for all my short-haul Y flights now, and adjusting my travel dates where feasible to get availability.