They have their own personal subscriptions to play.
To the best of my knowledge, they don't play on the NA servers. They play on the JP data centers that are much lower in population, and where houses are usually available.
The request is for them to experience the game as NA players experience it so they get a better understanding of our frustrations.
LotRO's base housing system in similar to the FFXIV ward system. You have Neighborhoods. Neighborhoods are increased on a per world basis as demand on a world increases.
Demand doesn't increase in that game (at least when I played) because in all other respects, their housing sucks. Tiny placement limits, placement can only be done on pre-designated hooks and other really unsatisfying design decisions. I did a little google searching on their housing about 6 months back when trying to research differences between FFXIV house and housing in other MMOs. LotRO housing doesn't seem to have changed. Perhaps one of their current players could give more insight if there are any in the FFXIV community.
I would imagine they summarize feedback on topics they've been asked to monitor then translate before forwarding. I'd be more interested in finding out how well the translated summaries convey our actual feelings. We know they do pay at least some attention to NA feedback, though a lot of that attention seems to be focused on the popular content creators. I'm not certain how much they pay attention to the forums.
Humans are really good at filtering information based on personal experience. Two different people can be given the same information and come to two totally different conclusions when their personal experiences vary wildly. It's why idioms like "before you judge a man, walk a mile in his shoes" exist. Sometimes you need to see things from another person's perspective to understand.
Do the developers truly understand the frustrations of NA players when their personal playing experience (as opposed to their development work) comes from playing on the JP worlds?
Most (if not all) Blizzard employees also have to pay their own subscriptions for WoW. I would imagine other large game developers are the same way.
That's actually common in business. In some countries, the market value of the game subscription (or whatever product/service the company provides if they were to give it to their employees free) would have to be reported as taxable income and sometimes could fall into category of bonus wages that are taxed at a higher rate. Both the company (less ""paperwork")and the employee (a few dollars saved on income taxes) stand to benefit if the employee just pays for it on their own.
People love to see their employers as stingy but a lot of times it's laws that are at fault.