Also created by established businesses by introducing unncessary services/products that consumers come to expect from that market - in hope of removing future competition.
Lavish shops for example. Not many startups can compete with a bank's floorground of today. But 200 years ago any shack would be an acceptable bank; Barrier to entry.
Whether these are genuine evolutionary steps in a market or an active effort to kill off competition... well, we'll leave up to your paranoia.