Can I change which switch controls which light?
Why are light switches so often wired in the wrong order. For example,
  on a single board, the switch closest to the hallway is for the lounge
  while the switch closest to the lounge turns on the hallway light.


Because money. Paying someone else less money to do a set amount of work is a way to increase profits. The electricians for tract (non custom) homes need to do the set amount of work in the least amount of time to increase or even have a profit. There is no motivation for them to care about the switch order and a motivation to not care as doing so would take time.


  Is this less likely to happen in luxury homes?


If the luxury home is a tract home, then probably not. If a custom home, then absolutely! I would even say that it does not happen in high end homes as the home owner is very involved and the electricians are used to working with such clients, everyone knows that the details are important


  Can I fix this easily myself?


Yes, if the wire tails are long enough. It can be as easy as pulling off the cover, pulling the mount screws and moving the switches (no rewiring). Turn off the power at the panel first of course