The Wales international has had a stellar career at the Spanish club so far, having won 10 trophies since his £85m transfer from Tottenham Hotspur in 2013.
During the summer transfer window, United manager Jose Mourinho admitted that he wanted to sign the 28-year-old, but Bale has suggested that he is content not moving to Old Trafford to become the main man.
"Well there's an argument for that, but I think the main thing, when you look back on your career, is that you look at your trophies," Bale told the Daily Mail. "In the end that's probably the most important thing."
The Welshman has made three appearances in La Liga so far this season, scoring one goal and producing one assist.