A very interesting article but I have to politely disagree. Firstly because no proof of times existence is given or referred to. Specifically no proof is given that as things move change and interact, a thing called time needs to exist, or 'passes'.
From the outset the suggestion "The laws of physics allow members of an exceedingly advanced civilisation to travel forward in time as fast as they might wish." May be seriously flawed.
Relativity, as in GPS systems for example, does indeed show that fast moving objects 'change' more slowly. And as they do so it can be said the surrounding matter effectively changes more quickly. Thus a fast moving astronaut might return to earth finding it very different than might be expected.
But unless proof is given that time, and 'the future' actually exist, all this proves is that matter exists, moves, changes and interacts 'now' -at different rates under different conditions. And not, IMO, that time, the future, or time travel may exist.
(Note, in 'electrodynamics' Einstein only -states- that a rotating hand on a numbered dial (a 'watch') shows the existence and passing of a thing called time. But logically, no matter how many people assume this is correct, without actual, scientific, experimental proof, all such a device shows is that motors can rotate hands. And thus SR only shows that moving motors etc run more slowly than (relatively) stationary ones).
(Auth-A Brief history of Timelessness )