Because the loudspeaker business is all about price points. You know, that if you pay 4 times the price, you won't get 4 times the performance. But people need to know, that they own a speaker which was 8-12-25 or 100 grand.
Don't forget, Revel isn't a korean/chinese Loudspeaker company. They are in the Top-Tier if you don't count those ridiculously expensive Audiophile things which cost over 100k (although, those are often not much better). So they don't want to look like a company, whose most expensive middle series loudspeaker is just 4,5k. No one cares, if it is better than other speakers from KEF/B&W/Polk/etc. Because those manufacturers have speakers for 8 grand, while the Ultima starts at only 16-18 (?!) so there is going to be a huge gap, which is not good for the market
I'm working in the automobile industry, why do you think nowdays all the Premium manufacturers (BMW, Audi,Merc etc.) have at least 50 models (with all the engines, cabrios, roadsters, limousines, 3 sizes of SUVs, Tourings, small cars etc.) ? Because the more pricepoints you are able to cover, the more customers you are going to have.
And from the post of the Revel guy, it seems they were also shocked how good the F208 got, and I think they weren't able to distinguish the F308 in those fancy Double Blind tests.
but if it is so good, they would have to be fools to sell them so cheap.