Will a potted palm die if it is rootbound and not transplanted into a larger pot?
I hope not. I just transplanted a bunch of rootbound palms, including a couple of new ones. My understanding is that palms actually like being a little rootbound. One of the S. minor "McCurtains" I just got was literally busting out of the pot yet still looked exceptionally healthy.
I did notice those rootbound palms suck up water like mad, so make sure you're giving them enough water.
It's not that palms like it rootbound, its the fact that when there is excess soil mix, the result is excess moisture that is unusable by the plant, resulting in possible rot.
Eventually, root bound palms or any other plant, will start growing roots that encircle the container and choke each other out, with many roots dying and taking up usable soil space along with a host of other detrimental outcomes.
The key is to figure out when to intervene, because often plants will not show signs of distress until the negative process has already become established.
In my other post, root-pruning, I outlined a possible way to overcome this problem, by initiating the formation of new feeder roots while maintaining the architecture of the rootball, hence not disturbing the root system in a dangerous way. I haven't tried it yet, it is just an idea. I may try it out on a small King Alexander palm. Archontophoenix alexandrae are supposedly sensitive to transplant and root pruning, so if it works with this species it should work with any.