Takeda US focused on developing Dexilant while Japan focused on vononprzan.Takeda was trying to get out of the primary space and into specialty so they de-prioritized anything of the sort (including Dexilant) in the US. If you know anything about Takeda, the US division operates very differently than Ex-US. Phathom was created by Tachi, a famous GI who was the CMO at Takeda. He didn't agree with their US strategy and created a new company (phathom) out of the licensed rights to the drug.
There's not a crazy conspiracy here like you want troll boy. Move along.