YoshiP has said that increasing interior item limits are on their list of things to do though not when it might happen. I doubt they're ignoring it but they do have other housing issues they're trying to address over the next few months.

It's also not something that was strictly a PS3 problem. SE did double item limits after PS3 support was dropped at the start of Stormblood. Now PS4 players and players with older PCs have loading issues in housing. SE can't double item limits if clients for those players will crash when in housing. They would need to wait until they no longer support PS4 and increase minimum system requirements for PC.

If you want to experience the problems larger item limits can cause, check out RIFT and visit the big Dimensions players have made available for viewing. Being able to place 2500 items sounds great but the result ends up less impressive when it takes you 3 minutes to load into the Dimension and then you watch items randomly appear and disappear as you move around. A lot of the limits we have are nothing to do with what technology is available to game developers and everything to do with what the average player has available at home.