Investing in one-trick ponies is a sure way to loose your money.
The problem with the mobile space is not that there is not money to be made. There is plenty of money to be made. But the apps getting hot cannot be predicted and a company with a hot app will most certainly not reproduce this with their subsequent releases.
The problem with the mobile space is not that there is not money to be made. There is plenty of money to be made. But the apps getting hot cannot be predicted and a company with a hot app will most certainly not reproduce this with their subsequent releases.