Could it be that the new macbook pro's are waiting on the announcement of the iPhone without a headphone plug? It makes sense to finally give the macbook pro's a lightning plug (and drop even some usb-B?).
If the new MacBook pro's come out now with an old headphone plug, the only device being able to use the EarPods is the iPhone (and maybe a new iPad)
If they announce macbook pro's now with lightning plug and no headphone plug it will be too obvious for the new iPhone's and that's something they certainly not want.
After all, macs are only 12% of the entire apple revenue.
If the new MacBook pro's come out now with an old headphone plug, the only device being able to use the EarPods is the iPhone (and maybe a new iPad)
If they announce macbook pro's now with lightning plug and no headphone plug it will be too obvious for the new iPhone's and that's something they certainly not want.
After all, macs are only 12% of the entire apple revenue.