Well, for all applications which don't require to addres more than 4 GB memory, a 64 bit machine is overkill. This especially applies to embedded systems (which make up the majority of all systems). This is unlikely to change for the next fifty years.
Well, if the consumer market thinks that 64 bit architectures are a core benefit (for whatever irrational reason) and are willing to pay for it, industry will/does deliver. It's still overkill for all but a few applications. But I never saw in my more than thrity years in embedded systems that a company did well on a long term when wasting money for non-essential capabilities.