7Nm is going to be used in multi billion dollar markets such as cellular phones. Until BTC goes up in price the entire mining market is only $400M right now for everyone. Even if you were 25% of the global it's barely going cover the investment of 16Nm right now. Most large companies make a number of different iterations of a desired processor before releasing the final product. There are a lot of hidden costs in R&D and development that would not make 7Nm viable for some time without an increase in BTC price.
Regards,
yan