Why won't Rega or Creek or another make a simple remote controlled five channel integrated?
Because they are audio companies that specialize in designing stereo music reproduction systems. Multi-channel systems are primarily a home theater concept and MC music is still a very small niche market. I seriously doubt Rega, Creek or similar company could make a profit on a 5 channel integrated and it certainly doesn't fit their current business model. Keep in mind that neither company makes an SACD or DVD-A player, either.
If MC music does become a mainstream product (which is not yet certain), then I would expect Creek, Rega and similar companies to begin designing and building products for that market.