Radeon 7 is a rebranded instinct card. It's cost of development was subsidized and it's still outrageously expensive. To bring out a large Navi chip requires AMD to fund the engineering, QA, software development, channel inventory, marketing all PRIOR to selling a single card. It's roughly ~$100M cost they have to carry and may not see a return on for months. For a company with AMD's financials, launching CPU's, motherboard chipsets and midrange GPUs (which requires arguably more inventory) it's just not attainable. Especially when they can just launch it next year on 7nm EUV for way cheaper.