As far as I know, currently there isn’t a platform that has incorporated AI into their advisory platform.
Well, so why is the title of your post "*Is* AI the New RIA?" The present tense implies this is happening now, not in the future.

The business model of even the biggest (which is not the same as the best) robo-advisors is NOT sustainable. A large team of software developers needed to implement and run these websites cannot be sustained on a few tens of bps quickly going down to zero due to the "land grab" by new entrants.

There will always be a demand for advisory services...
Wishful thinking. If the younger investors are Internet-savvy enough to currently use robo-advisors, they are also smart enough to in the near future figure out the basic premises of asset allocation and get rid of intermediaries sandwiched between them and their ETFs. Just wait and see.

As far as providing a different strategy or portfolio composition...
It is a fundamental weakness throughout the entire advisory industry. Why? Because as a prospective client, I would have *zero* faith in any robo- or traditional advice if I were presented with drastically different asset allocations based on my identical inputs.

I see a greater threat to these platforms coming from traditional advisors...
Again, wishful thinking. The real threat to robo-advisors currently comes from discount brokers and ETF firms (re: Vanguard), who will develop the same or better capabilities in-house and offer them for free or close to free. That implies no acquisition of robo-advisors, and hence no lucrative exits for VCs who by now pumped hundreds of $ million into these ventures.