I wonder how much of this is affected by their being in data centers, rather than using a scalable cloud solution for their servers. Machines in data centers cost a lot more to run than virtual servers, and there are ways that you can make virtual boxes scale with traffic and demand extremely easily. This would translate to servers that add wards when everything is full, or that completely save reclaimed player and FC houses with an option to restore into a new plot.
To the original point, I'm seeing that most of the people in this thread hold the opinion I agree with: in order to properly maintain the bottom line, SE needs to show preferential treatment with limited resources to paying customers. So yes, this is absolutely a bid to drive subscription retention and generate additional revenue. That's what businesses do. Asking SE to foot the bill for keeping your house active while you're not even paying them is absurd--and it's incredibly generous that they're giving even a portion of the house's contents back.
The only somewhat valid counterpoint is hardware failure, but asking them to plan for slipshod hardware is a bit absurd (it's like blaming Best Buy for selling out of the 50 UHDTVs they had for $2 on Black Friday because your car broke down on the way). But even still, it's not as if you lose everything in this case, and working up the additional .5M-30M Gil to repurchase a plot so you can restore your house when you come back should not be too difficult.