This is certainly possible. However, if this is the case, SE is flatly not earning my subscription. The content design for FFXIV isn't deep enough to occupy the roughly 30 hours of play time per week that I have available to me - nowhere close. XIV's content aims to provide something of interest to everyone in a broad audience, which naturally means they don't tend to provide a lot of interest to any particular group. I've always interpreted Yoshi-P's statements on this matter within this context, which imply to me that he's aware people will likely take breaks, and aims to generally make this painless for players (if not something he'd recommend).
Incidentally, XIV's lengthy efforts to ensure players can readily catch up to the current content cycle also provide evidence that they're aware players will likely take breaks. So whether or not Yoshi-P was recommending subscription breaks from time to time, I think he's aware they're inevitable, and housing is the one area in which SE imposes significant penalties on players for doing so. It stands to reason a long-term goal should be to eliminate this anomaly.
Character data isn't exactly inactive. At any time, someone can choose to resubscribe and be accessing that data within five minutes. It's very much stored in a ready state. It's really not so different. I agree that it being a limited resource imposes a different set of considerations for now: my point was that SE should have a long-term goal of eliminating this resource limitation.
As for the other, I'm sure you're right for some. I do wonder how long those returning players stick around though, particularly if they can't find a new house to purchase. In any event, I can only speak definitively on my own perspective.
Firstly, I think the volatility argument is a little bit unrealistic. I'd agree if there were multiple meaningful Gil sinks in XIV, but I know for myself, the first house I bought was sort of a 'why not' decision. I similarly snagged a large for my small friends-only FC as a 'why not' decision. I had enough Gil, I couldn't see that there would ever be a use for it, and so I snatched up property. If, on the other hand, there were a half-dozen other solid uses for my money, I'd have only purchased housing if I really prioritized housing over everything else - thereby lending weight to your volatility argument. I honestly didn't consider the subscription implications at the time of purchase, because I wasn't bored at that point in my XIV career. It's only now that the house is an integral part of my in-game experience, an experience I want a break from, that I'm chafing.
As for better approaches to neighborhoods, I think the key is an opt-in system. SE built the housing system without regard to player preference, and I think that's why the idea of neighborhoods fell apart. One player might just like interior decorating, but nevertheless is a hermit; another might just want convenient merchants; a third might want access to the FC Workshop or advanced actions. No matter what systems SE imposes - demolition, monthly rents, what have you - the neighborhood feeling was doomed the split-second SE implemented a system that forced neighborhood types together with hermits who just wanted a house.
For neighborhoods to truly work, I think SE must make it voluntary, a choice that does not offer extra supplies of housing or other benefits. These neighborhoods should actually carry with them mechanisms to ensure turnover of people who are not fully adhering to the neighborhood goal (demo system for inactivity; maybe monthly rents in Gil). I'd suggest they also block out the ability to restrict access to your house's interior areas, so as to foster more of an open feel. Anyone welcoming the idea of a neighborhood can elect to purchase (or move) their house into this system as availability arises.
Moreover, had SE designed this system in a more intelligent and forward-thinking fashion, these neighborhoods would have been the only wards. All other housing would have been individual private instances. 'Demolition' in a neighborhood sense would simply relegate you back to an individual instance. Nobody seeking a relatively private house would be forced to participate, and turnover would be ensured to limit the number of inactive players at any given time. Even at this late stage, however, the introduction of instanced housing coupled with new, harsher requirements on staying in the Wards would quickly improve the neighborhood feel. Couple that with some structured game events at peak evening hours within the neighborhoods, and I think we'd have a remarkable setup that punishes nobody while ensuring a truly social housing system for the vast majority who want it.
It's a bit of a wild concept, and not a pleasant one. MMOs have long implemented various bonuses as carrots to encourage players to stay subscribed (content updates, consecutive subscription bonuses, discounts for larger chunks of subscription time purchased, etc.), but I've never seen one use a stick. Certainly it's SE's decision if they want to try this, but I know if at any point I discovered it was an intentional decision rather than the artifact of a bone-headed development choice some years ago, I'd quit on general principle, and likely never buy another SE MMO again. I expect entertainment companies to compete to earn my dollar, rather than threaten punishments of a sort if I don't continue to buy into their ecosystem.