The Premier League club have brought in the likes of Angel Di Maria, Daley Blind and Radamel Falcao in recent weeks but were reportedly also interested in Bayern trio Thomas Muller, Arjen Robben and Bastian Schweinsteiger.
United manager Louis van Gaal has worked with the three Bayern players at either international or club level previously but all three remain at the Allianz Arena ahead of the German champions' UEFA Champions League opener against Manchester City on Wednesday.
Despite United investing heavily in their new-look side, having missed out on European qualification last term, Guardiola maintains their financial clout was not enough to tempt his big-name players.
"They didn’t have enough money," he said on Tuesday.
"I saw they spent a lot of money and it's good for my friend Louis. It's part of the game. All of the clubs in the world want the players of anther club but it depends on the player.
"If the player wants to play he will play. If he wants to stay he will stay. Manchester wants these kinds of players."
United will not feature in Europe during Van Gaal's maiden campaign after a miserable season last time out under his predecessor David Moyes in which the 20-time English champions finished seventh.
Guardiola feels United's struggles should serve as a warning for Europe's elite as to the unpredictable nature of top-level football.
"It's a good lesson for the big clubs," he added.
"They think 'we are unbeatable and strong' and they are not here and maybe the next season they are out.
"That's why football is magnificent. Every single week you have to be ready. Every week you have got to show you are ready. A bad 45 minutes and you're out."
