I bought the Microsoft Surface Pro (5th gen) in late 2017, and I'm glad to report that I haven't regretted it one bit.
Microsoft's rumored 2018 and 2019 product roadmap includes everything from a mysterious Andromeda to a Surface Pro 6 and lower-cost HoloLens.
The 2017 Microsoft Surface Pro, which isn't called the Pro 5 or Pro Next, is marketed as the "most versatile laptop." Laptop, not tablet.
A Microsoft exec has recently suggested there are no plans to refresh the Surface Pro 4 with Kaby Lake SoCs, so the HP Elite x2 1012 G2 will have to do.
Microsoft probably put off the Surface Pro 5 announcement enough, looking at a commercial launch by March 2017 with an Ultra HD display in tow.
Microsoft may have the future of the Surface device family all mapped out, with small rehashes in the works this year, followed by major upgrades the next.