Vitalik: The Ethereum Foundation sells ETH to pay ecosystem developers

Vitalik Buterin clarified in a post that the Ethereum Foundation is selling ETH to pay researchers and developers responsible for the following:

1. Ethereum will not consume 5 million ETH per year for proof of work;

2. User fees are currently low;

3. Transactions can be completed within 30 seconds instead of 1-30 minutes (EIP 1559).