There is little reason to add bits to word size. 64 bits give you any reasonably big integer value, any reasonably precise floating point number, and any reasonable address in memory. Adding bits to that has little effect, it just extends the range to the 'less reasonable' area. Yes it can be useful in certain applications but it won't bring effect in most.
What's interesting is having the computer to process them faster or more of them at once and because increasing the frequency is getting increasingly hard due to speed of light limit, adding CPU cores and massively parallel units such as GPUs is the current way to go.