They never had in mindd to reserve this change. Major money they earn are from mobile. The reason they did lock trading are two;
- gambling and laws in some countries
- They are greedy for money and the never liked that items from pubg were sold in other marketplaces without giving them any %.
People are playing this game because is very popular in asia. In europe (idk what about usa) game is almost dead. More people are playing in europe apex or even csgo. (talking only about steam version )