Consider that some of the C23 changes have in fact cleared up ambiguities and removed support for ancient hardware. So I find that the renewed pushes behind the standard are not all promises of eventual disintegration. There are a few accomplished and considerate people in WG14. If you visit the page I linked above you'll get a sense of that.
I never particularly cared about ISAs - when I think about the "simplicity" and "closeness to hardware" I mean the control over data layout and control flow. Data layout and architecture of the global data flow is often the key to 90-100% of the performance gains you can expect; and more or less stable binary interfaces mean interopability and modularity, minimizing ecosystems lock-in. Where you need to use a certain instruction is the rare case, and you are recommended to code it in assembly or using compiler extensions.
I never particularly cared about ISAs - when I think about the "simplicity" and "closeness to hardware" I mean the control over data layout and control flow. Data layout and architecture of the global data flow is often the key to 90-100% of the performance gains you can expect; and more or less stable binary interfaces mean interopability and modularity, minimizing ecosystems lock-in. Where you need to use a certain instruction is the rare case, and you are recommended to code it in assembly or using compiler extensions.