Regarding the travellators, they are not broken but are switched off at night for energy saving purposes between the hours of 00.00 and 04.00. This applies to the C Pier travellators in T1 and the airside ones in T2, as well as those along the skylink. They are switched on by Terminal Control at 04.00. As very few trains and buses arrive between these hours, it is uneconomical to keep them running. If I'm on an early shift, I always walk the length of the skylink when I come on at 5am and start up any travellators that haven't already been switched on. I make it my personal responsibility
Regarding the car park/hotel buses, many hotels and independant car parking companies choose to drop off/pick up at the station because it is easier for them to do so at this one central point rather than going to all the terminals. It is their decision to do this and has nothing to do with the airport. The areas outside all three terminals are now open for these buses to use if they want to but many of them have chosen to stay at the station for their own convenience. All MA car park buses, ie - Shuttle Park, T1/2/3 Long Stay and Premier Parking, drop off and pick up outside the terminals.