Rumblings from GDC suggest there is a path for devs to make Helix exclusive games that allow devs to optimize and build specifically for the specification and feature set. The goal seems to allow for devs to easily take that work, and use it create what would be considered your standard PC port that works on all capable PC's. The ROG Ally does not contain what will be the Helix's standardized configuration, so I do not agree.
I'm not saying you're wrong, I just don't believe the information one would need to make such definitive statements, such as the one you are making, is available as of yet.
Edit: to be clear, devs don't have to only target that Helix configuration exclusively, just that reports suggest that will be an option.
Edit Edit: This seems to be referring to what I am talking about.
https://www.notebookcheck.net/Insid...box-exclusives-and-block-Steam.1249902.0.html
"As Microsoft's Game Development Kit (GDK) evolves, the insider expects it to prioritize the
new Xbox console. Devs would first ensure compatibility with the
AMD Magnus-powered Helix
before a title supports Windows."