I've done work for TiVo in the past. Granted it was like 7 years ago, but at the time they had a very limited budget for secondary projects like this. If that's still the case then it may be that they only had the budget to develop for one platform for launch so they chose the more popular one. It may seem like bad business, but TiVo is a relatively small company that still rarely turns a profit. If they didn't have budgets they'd likely go out of business completely.