The only point of being in the executive club is if you are silver and gold (or their special higher tiers). It costs a lot to reach these levels, and a lot to stay in them. So yes, they don't encourage loyalty any more unless you spend in the five figures £ per year with them.
Prior to the changes in 2003, it wasn't a bad program, nowhere near as good as the US carriers, but still not bad. But even back then they wouldn't treat you any better if you flew a lot with them but had no status. They don't really recognise (what the yanks call) 'Butt In Seat' miles. You could fly 100k miles with them in the cheap seats, and they would still check you into a middle seat, with somebody who never flies them in the window seat.
It's their choice, and nobody makes anybody buy their tickets.