If you read what sama is quoted as saying in your link, it's obvious that "unified model" = router. > “We hate the model picker as much as you do and want to r

If you read what sama is quoted as saying in your link, it's obvious that "unified model" = router. > “We hate the model picker as much as you do and want to return to magic unified intelligence,” > “a top goal for us is to unify o-series models and GPT-series models by creating systems that can use all our tools, know when to think for a long time or not, and generally be useful for a very wide range of tasks,” > the company plans to “release GPT-5 as a system that integrates a lot of our technology, including o3,” He even slips up and says "integrates" in the last quote. When he talks about "unifying", he's talking about the user experience not the underlying model itself.