I don't think they will produce any house deluxe expansion after Lions of the Rock. It would be competing against the preexisting expansions. I expect things to be a bit different. Maybe boxes that put forward houses that don't currently exist in the LCG as neutrals or dual houses, with other cards expanding them, like they do with Warhammer Invasion, or maybe they will shift the boxes to be more thematic and the chapter packs will be more general, so a kingsguard box and the next cycle is just something that is applicable to more houses or more general themes.
I don't expect them to just stop though.