It does indeed appear to have been a very smart choice for Lisbon, but that does not address the question of whether this was the main reason for the location selection.
When Paddy (and the WebSummit Team) decided to leave the Dublin chaos, they had a choice between several cities. Lisbon made the best case on many factors. There must have been an "incentive" for them to move beyond simply having a "better venue" or "sunny weather", we (the public) will never have the full picture of the terms of the original "deal" between Paddy and the Lisbon/PT authorities.
Feels like it's been a "win-win" for everyone (except perhaps the "locals" who have no interest in tourism/tech and have been priced out of their rental accommodation by "AirBnB Landlords"... it's the SF apartment price squeeze all over)
If I were to guess the reason for the selection of Lisbon, it would be this: the Web Summit organising team have to spend much of the year in the city where the event is held. They chose a city they want to be in for their own reasons.
e.g: Weather/Climate, Food, Culture, Night Life, Scenery (lots of city parks, cycle/pedestrian areas), Architecture, Surf/Sailing, good International Schools (for those who have children) ... Mostly still "cheap" for visitors.
There's a good reason why people say that Lisbon is like SF but with better weather and more affordable.
