Note that the Arlada Express train does not have a paid exit, and the 75 SEK (~10 USD) fee is you're on a monthly travel card going by commuter train.
If you simply get a one way ticket on the commuter train (130 SEK or so), the exit cost is included in the price.
There really isn't a difference from some of the other train lines (Further than BÃ¥lsta requires an extra ticket, as does travel to Gnesta I believe).
Also, you can get a monthly card that actually includes the Arlanda station fee.
Obviously, neither taxis, private cars, Uber et.c. get to drop you off where you are.
However, the pre-filled line with cabs is regulated to be only Taxi Stockholm, Taxi Kurir and Taxi 020 to my knowledge.
Others can just simply pick you up next to that queue.
Basically, you've been misinformed.