Just like everything else in life. People will love one company for doing something and put it high in their regards, yet another company will come along with the same idea and concpet, but its just not "vintage". Human/Guitarist nature.
I would just be pleased if someone released a P-90 for a 7 string guitar. I know they aren't exactly popular compared to 6 string, which is fine. But the fact there are only a handful of decent pickups for 7 sring guitarist in this day and age, i find a little disgraceful. It seems to me DiMarzio have the best selection, but they are just trying to copy 6 string designs. How about pushing out the boat a little and designing a whole new pickup?