You can't buy a mass-market computer that doesn't have either an obvious backdoor or proprietary firmware right now, except for the one Chromebook that Libreboot supports.
And even then, your RAM has proprietary code running on it (I'm not aware of any DDR4 that doesn't have embedded SoCs for initialization, none of that is done in CPU firmware anymore), your hard drives can have up to entire embedded SoCs with proprietary code running on them, and there isn't an unencumbered 802.11AN wireless chip in existence. The only bright side to that is none of that hardware has system-wide access the way these backdoor coprocessors do.
I doubt we can get Intel to change directly. Most people don't buy from them directly anyway. My belief is that we can get OEMs to consider this a serious issue, and have them turn into a market pressure on CPU manufacturers. After all, OEM's life would be simpler if Intel simply didn't put the IME that everyone wants removed.
>After all, OEM's life would be simpler if Intel simply didn't put the IME that everyone wants removed.
Most people don't know that IME exists, they won't know either. You won't see an uproar from the consumers, because there are few that care (us). You are better off informing the general public in my opinion.
EDIT: I'd actually put money into RISC-V products instead.
It seems like their current devices are sold with me_cleaner being ran, along with removing several "fuses". Which is pretty good.
I'm still unsure if buying these laptops actually sends a signal that this isn't OK. Intel gets their money in the end.