He gave the Obsidian example, which is a great one, so no. Obsidian shows you can still do well as a noted app company if you are selling the right thing (sync).
There's work arounds (for example I forgot the name, but one plugin allows you to setup onedrive to share just one folder via logging in on each device), but the syncing story wasn't great. Quite a bit of extra setup across all devices, more points of failure etc.
Hence the smart business model, of let us handle it for you for a small cost.