Building a app or company, depends on markets, it is independent of technology. My Alma-Mater taught functional programming and outdated technologies, and I thought it was useless, but generally you can abstract away these ideas to be used in a new framework. Be technology agnostic, I am pretty upset about swift too after dedicated many hours to learning objective-c syntax. The most that swift would add to the over head is

1. new syntax 2. functional paradigm on top of the oop paradigm, and a new way of thinking.

Everything I know about oop stays the same and design patterns more or less the same!

Many of these companies started off small and built a market focused product before going full R and D.

As you can see these companies are looking to sustain their empires, so they have to "innovate" in someway, it doesn't mean you need to adopt new features.

I think your problem is your software design skills possibly need to be more TDD and at the same time hire some VA's to handle customer support tickets.

At the end of the day its a product in the market, not the product written with the latest framework, when you have market traction and a business case, and lots of funding, you can worry about catching up with the times.