Trying different business isn't yet the problem,they all probably may float down just the as the Fuel station did. They've been businesses that has survived over the years just with one single trade and they are still on the limelight.
They probably may want to consider a proper management skill,and a good study of how the business works instead of trying various slot.
Another view that speaks to my inner voice, the management of any business is very important as well.
Thanks for giving me another way to look at it