I think having good optimizing compilers goes a long way. I.e., to the extent they reduce the need for source code to cater to the underlying CPU, less effort

I think having good optimizing compilers goes a long way. I.e., to the extent they reduce the need for source code to cater to the underlying CPU, less effort is needed to port software to a new CPU. I think GCC and especially LLVM are really reducing the barriers to bringing new CPUs to market. Maybe for GPUs as well because of shader compilers?