Unfortunately, that scenario is always possible. I'm not saying likely yet but the authorities can always change the goalposts whenever they want to many peoples' detriment.
However, on a more optimistic note, those authorities havn't changed things beyond what those already living here have been able to afford before - ie grandfathering rules.
What the future holds, well no-one knows. Personally, I'll never reject my Brit nationality nor will I ever overstep the amount of time I can spend there in any one year without losing some tax status.