It's worth bearing in mind that Rubicon make plastic kits, which involve a significant cost in terms of design, mould production etc. Once a kit goes into production, the sprues are largely 'set in stone'. So they need to focus on the more 'useful' vehicles, to justify the production costs (unlike a resin manufacturer, which can knock out components for more obscure variants fairly easily). We'd all love to see certain vehicles in kit form (I'd be overjoyed to see some early war British armour, for instance), but we have to be realistic.