There was a time it was possible but it got used out of the context of what is was for.
People would at that time have no extra bases, therefore they would route Stockholm - Heathrow - Madrid and build a second base by routing through places. Which is against the spirit of the game in a lot of ways. Once bases was added airlines became more restricted and can only base in common economic areas, so the dates of EU Openskies are more accurately modelled. Under the last system people could effectively base elsewhere and pretty much anywhere at any time.
I mean it would be nice to pick up passengers and do stuff this way, but this is a Simulation/Game and people would seize any advantage they can get. This would upset the balance we have, I feel the basing and base limitations are fair and work pretty well at making a balanced game.
Besides, 20 pax routes or less can be profitable, however you have to build your airline specifically to do that, it is possible and it can be great fun. Tech stops on long haul eventually become all but irrelevant, only being used on ULH sectors.