Why wouldn't they? The franchise started on PC and has all 3 on PC why wouldn't the fourth be on PC?
You might have confused it with GTA, Mass Effect launched on Xbox first.PC nearly 6 months later.
Am sure EA will have it launched on PC.
[Edited by Aavonstar, 7/12/2014 9:29:58 PM]
Technically there will be a 4th title... but its not ME4. If you follow me.
I get what you're saying there will be a fourth Mass Effect for the PC but it will not be called that.