Plenty of people have been saying that the triggering of There is a caveat to this about how rules can be changed mid-course if there is the political will.
But more importantly, this account glosses over Article 50(3), as Andrew Lodder and Belinda McRae in the New Statesman have pointed out:
By virtue of Article 50(3), the other members of the European Council can unanimously decide to extend the critical two-year time period, with the UK's agreement. Importantly, this provision contains no specific conditions or constraints as to the terms on which that agreement can be made. Its wording is conveniently malleable. The terms of Article 50(3) allow the European Council to extend that time period until an alternative deal is negotiated and put to the British people by way of a second referendum. If the people approve the deal, then the withdrawal agreement is given effect. If, however, their choice is to retain Britain's EU membership rather than adopt the withdrawal agreement, the European Council can then use Article 50(3) to defer the effects of Article 50 until such time as the UK decides to invoke Article 50 again.
In other words, Article 50(3) offers a route to negotiating a precise exit deal for Britain and then holding a referendum which either implements it or decides to keep Britain in the EU.
That is particularly pertinent because the Brexit camp is deeply split. There are those who want to cut immigration even at the expense of Britain not having free trade with the rest of the EU, and those who want to preserve that free trade even if it means not cutting immigration.
Which means that when an exact deal has been negotiated, it is quite possible we will see large swings in public opinion - and thanks to Article 50(3) those could then be played out in a referendum.