Hmmm...in one case:

- Performance (which was a major driver) improved 100x-1000x.

- Reliability (other major driver) improved ~100x

- Codebase reduced, features increased, habitability dramatically improved

- Resource usage redcued ~10-20x

https://link.springer.com/chapter/10.1007%2F978-1-4614-9299-...

What would you consider a success?