My most optimistic feeling when it comes to 7nm was we will see SoC type chip early 2019. Anything bigger probably won't be coming until mid 2019 at the earliest. Meaning 7nm Vega (meant for their machine learning stuff) won't be coming out until H2 2019. Also it depends how good TSMC and GF refining their 7nm process for bigger chip. Worse we could end up seeing 20nm repeat.
Well. that's not exactly a problem. We know AMD plans to release a 12nm Vega and Ryzen lineup later this year, so 7nm chips in 2019 seems about right.
It makes me wonder though where Intel is with their process. I read a while ago that TSMC and GF 7nm is actually closer to Intel's 10nm, when measured by Intel standards. If this is true, them Intel still have a tidy lead.