If you follow this site, you will see there is a theme with Google - that theme is that they keep investing more and more into schema and markup. They keep adding more support for it and they keep encouraging webmasters and publishers to add it to their web sites.
Of course, publishers and SEOs are nervous about spending so much time on it when Google is known for removing support on many things they encourage webmasters to do. Most recently the news meta keywords tag but also like authorship, amongst hundreds of other features over the years.
But Google's actions, at least with schema or structured data have proven otherwise.
Now, Gary Illyes from Google said on stage at PubCon that schema is here to stay. Here is a tweet from Marie Haynes covering his keynote talk:
Gary says he knows G has a history of asking publishers to add stuff to their site and then dropping that feature. But, structured data will not change. It helps G better understand a page.@methode #Pubcon
— Marie Haynes (@Marie_Haynes) February 21, 2018
Truth is, nothing is forever, but at least in the next few years, I'd consider schema and structured data to be safe.
Forum discussion at Twitter.