It matters a whole lot less to Chrome because each page is itself a process at the operating system level. So the chrome browser itself can easily exceed 4GB in total but no one page can get beyond that.
I can understand people want 64 bit plugins, but you also have to remember that 64bit is going to cost some performance and waste some memory with a direct translation its not free to move to 64 bits. I want it to be 64 bit, but I have never run chrome out of memory, or had issues getting a plugin for it.