Name dropping does not mean a thing and I doubt they developed ALL the tools and IDEs for Siemens' industrial systems. If they did, then they would be wise not to mention the numerous SCADA faults found in Siemens control systems. There is absolutely no way you would roll out a system like that and have every industrial product line using it. So I am little puzzled by your claim.
The thing about these systems is they attempt to prevent you from shooting your own foot by not letting you aim. Some operations (such as erasing and writing flash) require you to do dangerous things like relocating code to SRAM and running from there while your flash operation completes. The details of each platform vary: ARM code is generated in a position dependent fashion; MSP430 is not.
I am certainly not calling C the end-all be all, but it's a tough system to beat. You could convince managers that mbedder may be the way to go, but it would be an absolute boondoggle to get existing engineers to use it. (They couldn't even convince the Park-o-matic folks to rewrite their code to use it). To a "C simpleton" like me, I would not call mbedder obviously better.