I agree with you that the issues could/should be solved with such a large company.
I would ask why they don't instance housing like they do zones. Have instances 1,2 & 3 for each housing area. This would triple the number of houses available while still keeping the "neighborhood" feel a lot of people like to argue about.
My only assumption is that SE as a company does not give the FFXIV team enough funding to upgrade the equipment necessary to do so, but it is only an assumption on my part.