I think it's true they will do stuff and it's also true they've signed up for a year of limbo. They were already prepared to go into this season with an interim GM, but even having moved on from that, and even given Dombrowski's short-timer/horse-trader reputation, he's not going to go crazy (and can't, without the $).
Harper and Boras are gonna have to keep quiet for now. By taking the 13 years, the no-trade and no opt-outs while making noise about raising their family here forever, they are kind of stuck until things get worse. The promise that was made to them was that the Phillies would have a high payroll and now we've seen the folly of that promise, because it doesn't always translate into wins. But they will still have one of the higher payrolls in the game this year.
Now, if JT doesn't re-sign and this team really does finish in last place and they start thinking about trading Nola and Wheeler, Harper would probably want off that train as well. But I could still see this team winning 82-86 games (not the roster as it stands today, but what they end up with in April) and being able to reload next year (when Cutch and Herrera come off the books and Segura no longer ties up money long-term). It all still depends on Kingery, Bohm and Hoskins - and on Wheeler and Nola staying healthy.
And if they do rebuild, it's not Harper who should have to ask for the trade - I don't see how the Phillies would want to keep him on the team and on the books just so he can DH when they are ready to contend again.