Was not the Holy Spirit promised to ALL believers of Christ??
Hold on there! If God let every Peter, James and Paul be imbued with the Holy Spirit, they might not feel the dependency on the Catholic Church to guide their every step. If that happened, they may read the Bible (for themselves!!) and conclude some of the Only True Most Holy Catholic Church has strayed from its first teachings. That it is,in fact, in error! That would cause a cascade of calamities if people started reading the Bible without a Catholic priest to "guide" them. It's too terrible to contemplate.
“Was not the Holy Spirit promised to ALL believers of Christ??”
Yes, I believe that is true, and I ask for the help and guidance of the Holy Spirit every day.
If you read the passage again you will see that it does not say that the Holy Spirit was promised ONLY to the successors of Peter, it deals with what we believe is an area of guidance that the Holy Spirit provides for the successors of Peter.