George,
When it counted, they were and there's no getting away from that. Do the Pats have the rings for those years? No. Do the Giants? Yes. End of story.
It may not be fair, considering the regular season records but that is the way the system works nowadays.
As I'm fond of mentioning you'll never convince me the 1988 Dodgers were better than the Mets, who were the best team in baseball that year and beat the Dodgers 11 out of 12 times in the regular seaso. Yet, the Dodgers beat the Mets in the NLCS and won the World Series and that was that. Nobody remembers what the Mets did except disgruntled fans like me, just like you remember the Pats; people remember the Giants as SB winners and the Pats are just remembered as having lost those games. No one remembers the losers in SB, just the winners.
Just enjoy the four you've won and try to forget those you didn't.