Steemit Inc owns 24%+ of all existing Steem. If they are in for the long run, then it shouldn't be an issue to concretize their commitment. This move could help reassure investors in regard to Steemit Inc long term commitment. Steemit Inc has been capital in the development of the Steem software so far and thus the importance of such a move would carry a lot of weight.
Maybe Steemit Inc could lock their current undelegated Steem in a smart contract that would allow them to power down only 10% of them every year over the next 10 years. This should be more than enough to allow them to cover the cost of their operations and if the price of Steem were to go up more than 10% a year this means their overall capital would increase over time. 10% is only a recommendation.
I don't know how complex such a feature would be to add but I definitely think it should be discussed.