I've played hundreds of games and I'm not sure a single one hasn't been decided by a "basic blunder", and I mean very basic. I bet the only games in which I've not committed one myself (and only gone on to win if it was overlooked, which they often are) were ones in which I fool's-mated someone.

There's chess-people's experience of the game, then there's how every single other person, including those who play it quite a bit, experiences the game. A "normal game" in the sense of the average of all games played, maybe that features very few basic blunders, just because chess people play so very many games (though huge numbers of people play a lifetime count of like ten to one thousand games, and never move out of basic blunders being pretty common, so I wouldn't bet on that describing an average game, but maybe) but the average person's experience of the game is that it's entirely about basic blunders, like, that's the main thing on which the game turns.