It's really simple.
Before: They were breathing their own exhaust and believed they were a player or two away. Examples of this thinking include: "Suh -- the Brady killer up the middle and we're SB bound" experiment; "Tannehill just keeps getting better every year, so let's draft/FA everywhere else instead" experiment; "Let's hire the hot, young offensive genius because we've got a complete team just waiting for him to exploit" experiment; "Let's let our first time HC have outsized influence on the draft and FA because we're just one player away experiment"; "let's over pay to keep key players around because we're just one more year away" experiment' etc.
After: The painful realization that the team is no where near ready to compete. So, they took a look around and asked the question: Which teams are competitive year in and year out and what part of their model do we like and want to copy? Examples of this thinking include: purging the roster of older, under performing, expensive vets; drafting a *possible* franchise QB for effectively a 4th and 5th (seriously, how could anyone complain about the risk/reward ratio here is beyond me); and more importantly recognizing that even if you are at the peak of your draft game you're only hitting on 50% so stock pile draft picks unless there is a specific player you have targeted available (and even then, listen carefully for better trade value).
On top of that, it sure looks like they hired some quality people to file the FO to make sure there are checks and balances on that part of the decision making.
Truth be told, we'll need a couple of years to fully evaluate if this year just looked good vs. was good. And even if this year turns out to be fantastic (QB turns out to be the franchise QB we've been looking), we still need to see how things go next year with $120m burning a hole in their pocket and the possibly very hard decision around drafting a QB next year.