Cheap fuel on orbit
May be the key to kick starting the commercialisation of space.
There are lots of old satellites in parking orbits, now they may not be able to refuel them as:
A: They weren't designed for it.
B: Their systems are probably dead.
However they do possess a lot of processed materials that have the potential to be recycled, this is currently not cost effective due to launch costs, I.e. it's cheaper to put a new unit it up, than trying to recover old units.
But... If fuel was available relatively cheaply for recovery machines to move them to a location (on orbit) where the materials could be reused the capability to create on orbit systems may start to appear.
Given current launch costs this could potentially be quite lucrative.
I realise this is very idealistic, but at the same time if there is no dreaming then we will never get there.
The main issue I forsee is that existing satellites use hydrazine for thruster fuel, making hydrazine on orbit may be a challenge and that units intended for refuelling may need technology updates beyond the refuelling mechanisms.