You can't run scared and never sign another $10 million reliever again but given what they got out of Nicasio, Hunter, Neshek and Robertson it's hard to fault the plan. All relievers break and many relievers are highly variable so at least make them cheap.
I don't think Ed is saying we need to spend $10 million on a reliever now, but that we should have when Hudson, Harris, Bettances etc. were available. YMMV.
My guess is they break camp at the luxury tax already, once the roster is actually set. The minor league guys still don't count now but the ones who make the roster do. Harrison probably has incentives. Should they get Miller again he'll be $1,000,000 or so, not six figures. And once you call up a reliever or an injury replacement from the minors that's another $1,000,000. They also might lose the Realmuto arbitration. Neris too. Depends whether they intend to negotiate.
They'll have to go over the tax at the deadline.
And we still don't know how January will shake out. A trade is still entirely possible.