Safe to assume, almost all of us wouldn't be here. Most nodes, in hashnode are open source topics. (Same holds true for stack overflow)
Running servers would be very expensive. Mainframes would thrive (vendors will make their stack compatible, and my not give a damn about other vendors).
Finding a Full Stack Dev in the said hypothetical world, would be same as finding an Architect in this world. The Idea of being a polyglot developer would be rare, if not absent.
Also, the emphasis of Programming Languages in the hypothetical world would be to run everywhere, even if it's not the most practical option. (Imagine C on the browser)
Most saddening fact would be, that development in general, would be vendor driven and not community driven. (The whole concept of community-driven-anything will be lost.)