To summarise, existing development/packaging/hosting technics are not able to keep up with the velocity of business demands that Wix is facing, so they are trying to develop a platform that would be at the highest level of abstraction, developers writing only business logic code, with deployments times at the level of seconds and maximizing of the utilization of resource. The solution is cohosting functions written in JS by different people/groups inside the same process, providing higher-level Wix-specific APIs for interacting and deploying them without any dependencies or packaging.

While the individual choices they made can be debated, the more interesting question is the software world is going in the direction they took?

I think it connects to the NoCode/LowCode buzz that going on now for a couple of years. If yes, developers of tomorrow would be separated into two groups, one enormous consisting of today business operation people who are going to write in DSL for highly abstract platforms like Wix and another much smaller in numbers even smaller than today software development community who is going to develop and maintain these abstract platforms. What does it mean for our careers if we want to keep enjoying high salaries? Should we seek to dig deeper into the internals to be in that small group of platform maintainers, or the real money would be in the creative usage of business DSL?

I vaguely remember VB and PowerBuilder days from the start of my career. At the time, people who specialized in business-centric development in these environments became quickly irrelevant as technology moved to the internet. So I myself have a somewhat skeptical and cynical view of such efforts. I prefer to have highly transferable skills, and being a single company business logic developer has limited value to the outside world.