There's no way that will end well.
SE implemented the demo timer as a way to free up a limited resource for players from those that aren't playing anymore, the only thing this would do is extend the demo timer to 7.5 months instead of 1.5. The people who were against the timer would complain about not only the further ineffectiveness of the system, but also that they now have to pay currency AGAIN to keep their house. The people who like the timer would complain that now they have to wait 6 times longer to have a chance at a house. SE would also lose on the potential subscription time which directly affects their profits.
But you're right, the ones who benefit are the ones who don't want to play the game for the next few months...
Lets try this from a different perspective.
I propose everyone who has a primal mount must pay 10 verity per mount every week or they lose the mount until they can buy it again for 99 tokens. This is fair because everyone who has those mounts makes endless amounts of tomes and can easily afford it. It also creates an incentive for them to not go after mounts they don't want and makes it easier for me to get them because i'll have fewer people to compete against. People that aren't using those mounts every day should just get rid of them if they don't want to pay, after all if they aren't using them then they won't miss it right? But we'll be nice and let them pay in advance so they can keep their mounts if they decide to not play the game for a while. That way they won't be hindered if they want to take a break.
Or how about lets charge a rent on glamors. You must pay a 10 HQ Steppe Serge each week per item you have glamed to keep your glamor. If you don't pay it then your item returns to its original appearance...
Or lets charge a rent on gear drops from savage, payable once per month with Ex token drops. Easily affordable if you do savage on a regular basis and if you don't then you don't need that gear anyway...