A useful distinction might be between micro-failures and macro-failures. A micro-failure means you roll an attack that misses, or your target makes their save, or you roll under the DC on a skill check. A macro-failure would be when a monster kills a party member, or the party is unable to turn back an orcish horde from sacking the city, or has to grovel to the evil dragon to save their lives.
Demanding macro-failures for advancement is unreasonable. Trying to tally individual micro-failures is impractical. In the end, a game is a game and the rules of the game are designed to facilitate fun rather than simulate reality. Probably best to just leave it at that.