It's called the salary cap people. There is so much parity in the league now a days that there is never a clear-cut Champion, until the Stanley Cup is handed out.
Both Vancouver and Boston won game 7 of the first round in OT. They were both 1 goal away from being eliminated in the first round.
It has little to do with grit, two-way play, natural progression, luck, etc. and a lot do with who's play well at the right time, and who you match up against. Every team that makes the playoffs (and some that don't) is capable of winning the Stanley Cup. It's absolutely great for hockey fans, and not so great for fans of one specific team.