Why are all services getting spawned? Can we disable that somehow or make it able to disable?
Why you say "no reason" ?
The reason is clear: cannot possibly know in *advance* which services you are going to want to use, since they will likely change with each flight, and especially during the arrival, since your are normally supposed to select a gate after landing, they'll all be created there because, if they were hypothetically created on demand, they would pop-up in front of you, which is something that most users hate.
Not that this is any different than how default ground services are spawned: they populate the airport even before you get there.