Let's think about this for a moment. Could it be lots of love from the Rovers's fans? Perhaps not. A few free tickets to watch lower league football? Perhaps not.
How about a good return on the investment? As building a new ground for a loss making League 2 club is high risk, the return must be high to justify the risk. It's not the same as a bank giving somebody a loan to buy a house as, if that goes pear shaped, the bank can repossess and sell the house. If a football club goes bust there is little resale value in a football stadium other than the value of the land.
So, high risk investment = big returns for the investors = a big drain on Rover's finances for years to come. (That's the best case scenario)