The best situation would be if Ionity and Tesla can agree to merge, or share standards so everyone can charge at all of them. But I imagine Tesla will not be interested until Ionity has parity, or nearly so, with them.
Ionity does not follow their own personal standards. It is the CCS standard. Tesla is the outlier who went with its own proprietary standard. And a post builtout agreement is not going to change hardware connectors on a car.
just need adapters.
Yep -- Tesla already shipped a Chademo adapter.
My understanding is that Tesla wanted to use a standard for their build out but the standards committee dragged their feet in order to stall them.
In Europe they do use a standard plug.