Lease-back props up the business (for now at least). This forces growth, and growth encourages lenders to invest in.... more new aircraft.
So growth is not a bonus to trumpet, it is an essential element.
So what happens at "level-out"? No more lease-back and all your costs are higher than they could have been (leases).
The loser will be the first one to level off. They will have higher costs, and all the investors getting twitchy because the growth has stopped. The winner will be the one who continues growing just long enough to mop up the remains of its big competitor just prior to raising prices to a sustainable level.
So which, of the 2, has a plan that allows the longest, most stable and sustainable growth? That is the real question.
The winner will have a rock solid reputation and public perception, the right level of well trained and willing crew, and a good product taking people where they want to go.