Agree or disagree, in both cases - but especially w/ Galvis - I think the Phillies simply value having him on the team more than he is worth to other teams.
And they might not be wrong. I definitely think the value of Hellickson's IPs plus the return they got for him likely equalled or exceeded the value of what they would have gotten for him in 2016, though not the value of the draft pick. And that's still true even though he was only replacement level, because the Phillies didn't actually have replacement level replacements for him.
Had Crawford not hit the wall in AAA for a while Galvis probably would have been gone. And while the completely aggressive rebuilding GM would have traded him anyway and just played Blanco or Florimon or some other scrub, that obviously wasn't what the team wanted last season.
The "danger" of losing Galvis for nothing is slim at this point because his value is so low. His max value was probably the 2016 trade deadline, not last year. 2017 he didn't really improve much (higher OBP, less power, but former still ridiculously low). Certainly he was not one of three best available SSs (I'm not even sure if one of those guys got traded).
I hope they take whatever they can get for him but with the questions about Franco and the presumed goal of a .500 team this year I think Galvis can add value, so long as he's not the starting SS and is a good team player about the super sub role. If that is anathema to him they should probably trade him. It's not going to bother me in theory if they keep moving Crawford around for three months, I just don't think you do it for Freddy Galvis. But if his value is, say, lower than what the Phillies got for Rollins and higher than what the Phillies got for Utley, it's probably still going to be that in July.