Then how do you define profitability? The title is "Best Regional Jet" not most profitable. And yes, I'm very open to being wrong (I even stated I was wrong on the prop thread you created when it came to fuel burn), but you keep moving the goal posts when you post arbitrary questions like this with no clarity. I have a formal education in competition and business strategy, so my understanding of how a business works and why is at a different level than most people that play this game, many concepts of which are counter intuitive.
Take a look at it from a restaurant perspective (I don't own a restaurant BTW). A $10 steak might have a 100% markup and be priced at $20 whereas a pasta dish will cost $5 with a 300% markup and be priced at $15. Which is more profitable? If you are a customer, you would probably say the pasta because it has a 300% markup whereas the restaurant owner will say they are the same--they both produce $10 in gross profit. This is why menus are priced the way they are--it doesn't matter what you order because you are going to generate a $10 in gross profit. It's the same in AWS.
What I think you are trying to as ask is which aircraft provides the greatest RONA (return on net assets), which again could be the E145 fleet group or the E195 fleet group assuming you are only flying one fleet type, but if you are flying both then the CRJ is likely going to be better because of the additional costs of having multiple fleets (especially the fourth).
Going back to your comment--comparing within a certain industry wouldn't be margin because of the exact example I gave with Walmart. Walmart has the lowest margins (3%) but the highest profit (billions and billions) so would they be the least profitable or the most profitable in their industry? The same goes with aircraft--is an aircraft with 50 seats producing 15% profit considered more profitable than a 100 seat aircraft producing 10% on double the revenue? The former has a higher margin, but the actual dollar value is going to be lower. Really the answer is much more complex than a simple blanket statement of which aircraft is best because there are simply too many factors at play in determining what is best (see your prop thread, for example). It also doesn't take into consideration frequency, which would be is it more profitable to fly that 50 seater 2x at 15% profit margin or the 100 seater 1x at 10% profit. You'd need a background in operations research to answer that one scientifically.
My definition of best would be best all around, which is why I stated the CRJ because of the flexibility of the fleet type. Given unknown airport, route demand/density, etc. then you can likely make the CRJ work in virtually any circumstance. Given defined circumstances, the CRJ isn't always going to be the "best".