It is true. In your specific situation, you spend almost 17 million on transfers over the last 1,5 month. And that's just since the start of december. That's quite some assets you have in your club. There is just never a single cause for bankruptcy, it may be one of the larger reasons for your financial troubles, but hey just selling off one of the 17M transfers and you're safe again.
In other cases teams seem to have 3 to 4 times the league average in staff salaries, or twice the average players salaries etc etc.
Really, an unexpected drop in revenues may be a large reason, but it can be just one of the many causes that influence your specific economy leading to bankruptcy.