At the root of it, the author is arguing that everyone needs to reach for common tools to patch together feature-packed solutions for a narrow set of customers. This somehow translates into it being cheaper to build and more appealing to customers. The problems I see:
1) Stuffing a bunch of third party services together to make a product is great for a startup looking to launch quickly, but in practice it is usually horrible long term. Quality integration between your features becomes difficult, and you will often sacrifice the UX as a result.
2) Outsourcing everything makes you a thin wrapper. Talk about commoditization.
3) The author seems to assume that the brand is the business, not the underlying product. That doesn't even hold for hamburgers, let alone specialized software verticals.
4) In an era of software being dumped on the market in droves, the solution is not to dump into the market even faster. I can tell you as someone coming from the medical side of things that people try doing this to us all of the time, and it's just endless heaps of garbage software. People would be smart to take the time to really think through our problems in the fine details where they matter. I know that doesn't mix well with a VC-backed growth at all costs model, but frankly that's not my problem.
The article feels like it was written by an MBA, not an engineer.