Can they even justify a sole E190? You have major carriers with large scale such as JetBlue and Virgin who have been very vocal about the Embrear, they are incredibly expensive to fix when broken, cost a lot to operate compared to the 737 or A319 and they have either dumped it or in the process of getting rid of it.
Engineering costs to fix one could potentially sink the entire company should one brakedown. This played a large part in Air Australia’s collapse. Small Fleet and extreme maintenance bills. The revenue just wasn’t there to pay for it all.