Is there a statement from them to this point ? I couldn't find it in the article.
But this isn't the point anyway really.
The users were not told. > IPhone owners were not informed that installing iOS updates (10.2.1 and 11.2) could slow down their devices
This means that the users would definitely just assume their phones were now in need of upgrade.
Also as for the trade-off between performance and optimisation, thats fine. That was there previously also.