No, it is not a myth. It is *economically* locked in. Technically, you can move it, but you lose your master node, and its reward. So you won't.
Every coin in every wallet of every crypto where people are holding and not selling is "economically locked in".
Partly yes, but only dash wallets generate money while in the wallet. If someone starts buying dash its not to like get 10 dash to pay his bills, but to get to 1000 coins (and that's what the bitcoiners do now) so he can start generating money/economy without actually doing any work. And this is way way more economically "locked" that you can imagine.