Well for starters pope Francis is not a saint and neither is John Paul. John Paul II however got canonized a few years ago and I assume you were referring to him, still that "II" is quite important as John Paul was his predecessor.
Secondly the Vatican has an entire department solely for dealing with saints. They have quite the rigorous standards to acknowledge someone as a saint, amongst others you need to be dead first to be considered and contrary to popular believe the Vatican doesn't want to canonize just about anyone and this includes popes. What you need to realize is that being a saint isn't just having some prestigious title, within the Christian doctrine saints hold an important position.
Thirdly you seem to be under the impression that the pope, or people related to the Vatican, automatically become saints just because of their position or location. Well they don't. Officially there have been now 266 popes (though that number is relative as there have been several wannabe popes). Of those 266 currently around 80 have been canonized (this number varies though from source to source, but mostly it's around 78-80) and of these 80 only 5 have been canonized in the last 900 years and for 3 of them that even happened during the last 70 years. All those other popes became saints during the first 11 centuries which was before the Vatican had created a committee to deal with canonizations. With other words they were never truly canonized, in most cases it just happened that whenever a pope died a cult emerged that venerated him as a saint. So at the time when the Vatican attempted to control canonizations, they had no other option than simply accept the saints that already had existed for centuries.
Same thing with all those other saints. Many of them date from those 11 centuries were there was no control. Also there are quite a lot of saints that never existed or even if they did, they never had any relationship with Christianity whatsoever. During the Christianization of Europe and the Mediterranean, one of the most popular methods to convert people was via assimilation. Instead if replacing their religious believes with Christian ones, they assimilated the former into the latter. So there are saints that in fact originally were local deities, demi-gods or legendary heroes of which we don't know if there was even ever a person they were based upon.
And as why we don't get many new saints anymore, well the procedure is strict and in a world where "miracles" barely exist anymore, it's hard to become a saint when one of the requirements is that you need to have preformed a minimum of two miracles.
