Open-source development is indeed an essential part of true decentralization. However, ensuring its long-term continuation is not trivial. One of the main difficulties is to produce incentives for other devs to contribute for the long term.
Here I propose a simple approach to deal with long-term open-source development for dApps that make some profit. dApps can dedicate a percentage of their profit to open-source development and manage it using ErgoTeam. Dedicating funds to be managed by ErgoTeam is very trivial and is even doable using smart contracts to prevent cheating. These open-source funds can easily be managed by ErgoTeam – community devs can create proposals and ask for necessary funds. Who the voters will be can be decided dApp-dependent, they may be founders of dApp, or the whole community of users.
In the latter case where voters are actually the users, the dApp development is guaranteed to go into the direction that users want. As long as the dApp functions and makes some profit, there will be funds for open-source development, and the whole process will be self-maintained. Moreover, if some core devs walk away for some reason, the development process does not halt.
ErgoTeam and the to-be-released Auction House will follow this pattern.