> If you change the license, all of the original work must still be distributed under MIT and only the work done after the cutover can use a new license.

That's pretty meaningless given that there is no obligation to distribute the source code to the new version, or to provide any way that "substantial portions" that are used in the new version can be extracted and used separately from the new-license work.

Meanwhile if you contribute to a currently-MIT-licensed project under a CLA, you have a copy of the current version under the MIT license and can continue to redistribute that indefinitely.

So what practical difference does it make?