> A commitment that this license will not change, even by the original author

Unless you’re entering into a contract with the project maintainer (which you’re not, if you’re just downloading or using it) then such a commitment means nothing.

Applying an open source license to your work means you’ve licensed other people to use it under those terms.

You can make all the commitments you want in the license, but it doesn’t actually commit you to keeping all future work open source as well under the law.

So you could write this license and make the commitment, but if you changed your mind later and decided not to open source future commits to the project that you made then nobody could stop you. Not unless you had entered into a contractual agreement with them and exchanged some consideration (money).