The Linux foundation is the founder

Do you consider The Linux Foundation to be the founder of all projects listed as "Hosted With Joint Development Foundation" or is there some other connection in this case?

all works are going to be published as open source

This doesn't mean that something is not an effort by corporate interests to control and co-opt a movement; in fact, quite often it means the opposite.

In this case it sounds like would-be institutional contributors to OSM (which uses copyleft licenses for data, documentation, and source code) will be encouraged to instead contribute to Overture-managed permissively-licensed (meaning non-copyleft open source, allowing proprietary derivatives) datasets and software projects.

The only reasons I can see why these four companies are spending $3M/year each (plus 20 full time engineers each!) on a new project instead of contributing these resources to OSM is (1) they can't have full control of OSM's priorities (although they could have a lot, with the amount they're spending here), and, probably more importantly, (2) a large amount of what OSM produces is copyleft licensed.

compare the Overture Foundation's membership options:

... to the OSM Foundation's:

(note that three of the four steering members of Overture are already amongst the many corporate members of OSMF.)