Bird
Rest in Peace
When I worked with a pipeline contractor all our welders only used 2 grinders. They were usually a 5" Makita. One would have a grinding wheel the other would be a wire wheel for buffing the weld.
Your pipeline welders' grinders are like my bench grinder. I do have some other wheels, but 99% of the time just keep a grinding stone on one end and a wire wheel on the other because the wire wheel is the thing that gets used the most.
I only had one 4.5" electric grinder and a little pneumatic angle die grinder; never even thought about having a use for several until I read this thread.