SLP being used only to breed axies and it has no other utility.
Yes, for the time being, but the Sky Mavis team is already planning to launch another burning mechanism that includes changing or upgrading certain parts of your axies, as well as the release of Project K, which I believe has a lot of new features that will rebalance the entire economy. If you look at the most recent article
[1] release, you'll notice that they have a plethora of triggers at their disposal in the event that the entire ecosystem fails.
Also, even though some of their economic adjustments appear to be anti-poor and make no sense, I can't pinpoint or question their decisions because I can't see the big picture, and they have more data at their disposal to give them hints on which aspects of the game that needs improvement. At the end of the day, the only thing that the investors can do is wait and let the SM team handle their shits. Remember that the people playing the game can only do so much.
[1]
https://axie.substack.com/p/dev-journal-economic-balancing