This is one way of looking at it. In my opinion, this view goes against progress. Let's stay in this perspective for a sec. You can mine "100%" and the devs have more incentive to dump everything and halt future development on the coin, because there's now zero incentive for keeping the system sustainable - unless the devs instamined a ton somehow. If the coin ends up having sustainability in mind, you end up in a situation where outsiders, not the users, buy a ton of influence and fund the devs that way. This is what's happening in Bitcoin right now. This is fine, but it's not what we want to explore here.

In the opposite perspective, that "10%" that you lose is an investment in the continued expansion of the technology - just like the network. It ensures the coin continues to progress and builds itself up. Just like the miners are doing a job securing the network, the devs are doing a job to make sure the technology is maintained and improved over time. Both things require a cost of resources, and what the development subsidy does is keep miners, users, and developers in harmony. The hybrid PoW/PoS system keeps everyone accountable. If you don't like what devs are doing with that 10%, stop mining, and they'll feel it - plus you have a voice to communicate your discontent by voting in the system. It's a check on devs, just like PoS is a check on PoW in Decred.