Earlier quoted context omitted.
They also don’t have very high barriers to entry for competitors. Replacing SAP is really hard after it has been established in a company. On the other hand replacing Slack is really easy. Same for Uber. Customers and drivers can jump ship anytime.
Uber has a big competitive moat, which is willingness to burn money. They've got a lot of it, and any competitor which can't raise as much money for that purpose as Uber has will lose out. It's simple, in any area that a small competitor of Uber operates they just artificially lower prices and do it until the competitor runs out of money. The company with more money wins. Slack... sure you can just spin up a rocket.c…
that's a very bad long term strategy :-)