[sgbuffett]

Most if not all biz has no entry barrier. If there is, then it is a monopoly. Even Amazon got lots of competitors but they can still dominate the market.

Grab is different from Uber which is almost entirely focused on transportation. Grab has more potential but they got a really big competitor in Gojek in SEA market. The other competitors don't bother them.

Amazon build up a logistics network that is a barrier to new players. It can offer overnight delivery in US...

To replicate this is too costly this is Amazon moat 

That is why JD has good potential in China to do what Amazon has done.