Of course. But it's so obvious, don't you think they could've figured it out on their own, without UA?

The fact that they have merged with UA, synchronized the frequent flyer programs, but never once made a mention of E+ is troubling.

CO's principle is to pack as many seats as possible in the smallest possible plane. They believe that you only make a profit on the last seat you sell. And while they will certainly monetize existing features (bulkhead, exit rows), and necessities such as checked bags, they will not go out of their way to take a risk and then count on customers paying for the monetized services in order to recoup marginal revenue.

Look at the BoB program. They have ridiculously undercatered each flight. In most cases, the BoB is sold out before the exit row. Are they doing this because they're foolish? Of course not. It's completely intentional. They will always pack a minimum of Bob (i.e. reduce their risk to near zero) so that a BoB meal never has to be thrown away, even if it means half the plane goes hungry (which is really not their problem).

E+ required UaCo to rip out all those most valuable "last seats sold." To me asking CO to do that would be like asking the Catholic Church to remove the Cross as the symbol of their religion.

The only way I see this even as a faint possibility, is only on CO's domestic fleet, and because of EUA only, which they hate. Here, they would remove a row of FC on their domestically-configured aircraft, allowing them to both install E+ and add a row of Y at the same time. Four seats taken out and replaced by six seats is the type of bargain CO would go for, because it would remove the 4 seats of FC that they virtually always have to give away for free, add E+, at no additional cost of soft product, and have more total seats available for sale.