The idea to get on this is that the pie grows it does not stay the same size.
This chart shows the production per person has risen to 5 times what it was in 2929.
That means by importing Chinese cabinets more people can afford cabinets than before.
This does assume that you have enough work. But to do more volume, "get to the next level" you would have to buy more equipment or hire more people. This would reduce your margin and you would have to make a commitment to paying off that equipment or increased expense of the workers.
Or you can do more volume by outsourcing. And spend time on what you do better whether it be promoting or installation or design. You clearly have an advantage on installation and design over the Chinese.
Even if the Chinese start building airplanes that does not mean the end of comparative advantage it could even flop the other way round as we now export oil meaning that we have an advantage on energy cost and we will start/are doing more manufacturing. Since their people are becoming better educated they may be better at stuff like airplanes.
Unless you don't have enough work you are better off outsourcing some portion of your work to allow you to do more profitable things with your time.