Charles has said multiple times that they are under contract through the end of 2020. In the event that the roadmap has not been completed, then they will continue working beyond that date. The ADA funds that belong to IOHK are not to be used for developmental funding. Those ADA belong to IOHK and act as an incentive for them to build a robust and sustainable product. Once the current roadmap has been fully implemented, then it will be up to the community to utilize the on-chain voting mechanism to fund the next round of protocol upgrades. These upgrades will be funded by the treasury.
The $62M raised was the value of the BTC at time of sale. Since the last trench was completed in Q1 of 2017, it’s very likely that the BTC were worth $1-2k each. It’s very possible that IOHK sold much later and actually has 100’s of millions in reserves. Nevertheless, that is not our business. The only thing that ADA holders should be concerned with is that IOHK is able to fulfill the contract to which they agreed. As of now, it looks like they clearly have ample funding to do this.