The problem is, where's the checkbox labeled "keep your 22 Gb of local models off my 256 Gb drive and keep your assistants off my battery" ?
Apple made the thing compulsory so we're not giving them the benefit of the doubt because they don't deserve it.
When I updated, I had to actively sign up for new Siri and even make space for it. Until update, my phone had the "old" Siri. Not sure what the issue is