It seems like Yelp won or did they? Google wanted to source third party reviews because their own review database was limited. Yelp wanted to keep getting traffic from Google but not have Google simply source their reviews on their site.
Google updated the place pages and they now have the new overall design, plus remove the third party reviews, except for a small link.
Here is a picture of Airmont Eats place page. I cropped it a bit, but you can see how Google is strongly encouraging users to write reviews, then shows only their reviews at the top with a small link to third party web site reviews from Yelp and others.
Based on careful thought about the future direction of Place pages, and feedback we've heard over the past few months, review snippets from other web sources have now been removed from Place pages. Rating and review counts reflect only those that've been written by fellow Google users, and as part of our continued commitment to helping you find what you want on the web, we're continuing to provide links to other review sites so you can get a comprehensive view of locations across the globe.
I'm really worried about all the small businesses I work with that just lost 2/3 of their review count because of the 3rd party reviews being gone from the count (and they're also not really displayed unless you dig down). I'm guessing you guys already thought this through but I've already seen tons of posts of business owners that seem very upset.
I guess time will tell, but I have a feeling those reviews are never coming back, at least not directly on Google Maps.