Why is this not the solution?

[Nepentha]

Apartments were specifically for anyone who could not get a house. Since houses are limited to one per server for account, I'd argue that includes alts.

They are only running out on Balmung. That is a unique problem to one server. No other server has this problem. Its not a flaw in the design. Still, I'd like to see more apartments allowed, because its not like its difficult what with them being instanced.

Not a flaw in the design, no. But we were told at the time they could easily up the number of apartments. Balmung is unique because it was an RP hub and one of the largest servers. That's changed, but a lot of people's alts still have apartments. They've either moved servers and left behind alts that have apartments, or started with fresh characters on other servers. Still, it wouldn't hurt for SE to see that and at least up the number of apartments on Balmung.