Why did Boston Red Sox owner Harry Frazee sell Babe Ruth to the Yankees?

It seems that Harry Frazee was in financial strife. His solution was to sell off Red Sox players, including Babe Ruth.

Frazee was involved with theatrical productions in New York. Because of their poor performance, he had to realise his other assets.

In January 1919, Ruth was looking for a new contract, along with the more than doubling of his annual salary from $7,000 to $15,000. The amount settled was $10,000, but Ruth's performance was such that the new contract would not be sufficient after he continued setting records for home runs. The upshot was Babe Ruth's sale to the Yankees.

https://baseballhall.org/discover-more/stories/short-stops/the-deal-that-changed-the-game