> The porting effort for software to run on x32 is a rounding error compared to what would typically be required to universally use offsets instead of pointers in dynamically allocated objects.
This kind of changes can be shoehorned into compilers and VMs. Even if you do not make changes to Chrome, just using something similar to JVM's compressed pointer in V8 may make it much less cache-hungry. The same argument can be made for any other JIT.
Also, please consider in the total x32 effort also the amount of changes, testing and support that compilers and distros will have to sustain to make x32 available to end users.