Not really, I have a Pixel 4a 5G that doesn't come with magic eraser but because I pay for Google One, they gave me access to it.
So I doubt there are really any limitations on the hardware themselves or that you absolutely need the new version. Google just paywalling the features.
I bet you all those will be available very soon for Google One subscribers.
>>Belphe+(OP)
Yes, but magic eraser is something that can be easily done off-device in the cloud. Real-time audio shaping cannot with introducing unacceptable latencies. There are no doubt some things they'll roll back to older Pixels, but they can't do everything new on this year's release without hardware.