That's technically true. Planetary Annihilation was a heroic effort lead by Jonathan Mavor (formerly of Gas Powered Games) that fused elements of TA, SC, and its own crazy ideas on what amounted to a shoestring budget.

Supreme Commander's budget was about $50M USD (circa the mid-2000s), and Mavor was lead engineer on the project.

Beyond All Reason is arguably more similar to Total Annihilation than Planetary Annihilation.

By that same token, Sanctuary is the closest thing to a complete remake of Supreme Commander. Granted, Forged Alliance Forever has had such incredible work put in by the community that it comes close, but it's ultimately stuck on the same engine.

Turns out Mavor has a new company now, and I'm elated to hear someone's finally combining Factorio with a decent RTS component:

https://industrialannihilation.com/