Aphids: Luck or something else?

I only ever get Aphids at the end of the garden where veg is planted in the ground,. but never on my patio, where they're all in pots.

The greenhouse this year my potted plants got covered in Aphids, so now I know it's not the pot putting them off (the ants moving them about I mean)

Theres several ants nests in and around my patio, I've seen them carrying the Aphids, just can't figure out why they never attack the patio plants?

Is it luck, or is there a reason behind it? The patio is plain concrete, flat surface. I have large patio doors, all glass. I haven't used any companion planting to put Aphid off, and there's only potatoe's, corn and courgettes one side, and tomato's the other side.

I keep thinking maybe the patio doors, light bouncing off might bug them or something, but can't find any science-type info about that specifically.