Vega on 14nm turned out to be too much of a power hog so AMD never pushed it into the mid-range as expected. (There wasn't much point if it couldn't get better power and speed numbers than Polaris.) So now they're doing a stop-gap to have something available to sell to that market until Navi is ready.
So far as I can tell Vega on 7nm is never going to be a standalone mainstream product, though AMD is doing it as a machine learning card, probably mostly to get some experience with working with the 7nm process. It might happen as part of an APU if next year's replacement for the 2200G and 2400G goes that way rather than using Navi graphics.