dumb it down ?
Another article here is "Intel, AMD team with tech titans for x86 ISA overhaul" where they have solicited the help of Broadcom, Dell, Google, HPE, HP, Lenovo, Meta, Microsoft, Oracle, Red Hat, as well as individuals, including Linux kernel-dev Linus Torvalds and Epic's Tim Sweeney. This makes me wonder if maybe speculation is a dead end, and needs to just go the way of the dodo. What happens if you remove all the out of order and speculation and allocate the saved resources to increase the core count by an order of magnitude of really simple secure by default dumb cores.
I'm thinking back to Windows NT 3.51 that ran on x86/MIPS and Alpha, where the drivers, including graphics ran in user space for security (and stability - you might see a message where the graphics driver had crashed and was restarted just like any other user process could be, instead of a blue screen of death - or a red screen of death - there are options to change the colour). The downside was that this did have lower performance, but the increase in performance for other operating systems was paid for with much weakened security. My rule is: "If a program can crash an operating system, it can probably be used to own the box".
We need to end the race after performance, and go back to the fundamentals. In the battle between security and performance, security should win every single time - there should be zero compromise. And if the saved resources can add 10x the numbers of basic cores, the overall performance hit should be minimal. If we get to the stage where every application has one or more dedicated cores, it will probably make a lot of things much simpler. And simple is the friend of security, complex has always been security's arch nemesis.