I think I made a post about how I was figuring the Regal's price was going to go up late last year. I think the LaCrosse will also go up again.
The Verano is ultimately the reason. The previous price points were because Buick needed to fit in the thin gap between Chevy and Cadillac. With 3 models, Buick can justify the overlap with the other brands.
And rimtrim, to answer your questions, all three models are doing great in their segments, so GM can afford to raise their prices. For certain products, including cars, the buying process isn't always heavily based on objective comparison like what you're doing. If someone wants something, the question is more often than not "can I afford it?" not "is there something that meets my needs for less?"
Whether GM is successful or not is yet to be seen, but I think this generation of GM cars is focused on trying to get people to appreciate subjective qualities foremost. I think that is a smart move because when a company makes a product that is designed to be measured against competition, it invites the competition to measure back. Commoditizing a product by making it the lowest priced or best MPG-ed or highest HP-ed devalues the brand of the product because if you are telling people they need to buy because of one of those reasons, what happens when your competitor out does you? Suddenly all of your advertising dollars have gone into convincing your customer to buy your competitor.
The solution is to make a value proposition out of the product being and not the product doing. For cars, I think the rule of thumb ignoring niche markets is to have objective qualities that won't embarrass the owner (which is a big task in itself), and then otherwise focus on subjective qualities.
I have nothing to say about the Malibu ECO in particular because it sounds like GM dropped the ball, but the Regal eAssist is a different ballgame because it is in a market with fewer competitors with good FE.