To be fair, Airport Express service in Hong Kong stops at all stations, so you might better compare it with the City Line service which departs every 15-20 minutes. It is decent enough though, if you don't travel with hundreds other commuters in rush hours.
I will agree here that decreasing frequencies is never a good sign for passengers, like us.
You're joking right?
Comparing Hong Kong's Airport Express with the Thai City Line service is like comparing Apples to a rotten Durian!
First of all, Hong Kong doesn't have a so called "City Line"
Secondly, "Express" does not mean "Non Stop" - get your facts right.
Last, but not least, the point we are arguing here is not how fast the "Express" is, but rather how frequent the service is. Nowhere did I say that the Thai Express train is not decent - it is fast and comfortable, but it just DOESN'T RUN FREQUENT ENOUGH!!!!
And for argument sake, if you do want to compare the speed of any "Express" service, the distance served should be the same otherwise it'll be another "apples to oranges"