[Bravada]

The only cars I can think of the size of the DTS are RR's, Bentleys (the Arnage type, not the "mass-market" Contis) and Maybachs. The DTS is a huge cow, make no mistake.

That said, there is market for large LUXURY cars. The thing is, GM still cannot figure out how to build a luxury car. Cadillac's only OK car is a continuation of a line of small cars started below the "actual Cadillac" in the 1990s.

The problem is also that GM doesn't have a clue and changes product planning everytime wind starts blowing in another direction. What survives are a few core models, sometimes ending up underinvested (Malibu), and some pet projects (Kappa, Volt).