ENGLEWOOD, Colo. -- After three consecutive playoff misses, after back-to-back seasons of at least 10 losses, a lot of things have been said about the Denver Broncos' offense and its growing list of struggles.

That the offense is outdated, that the team tried to do too much with Mike McCoy calling plays and tried to do too little with Bill Musgrave calling plays. And that the QB has been a question since Peyton Manning retired in March 2016.

But as the Broncos already have a trade in place for Joe Flacco as they prepare for free agency and the draft, their offense doesn't just have a quarterback problem, it has a continuity problem -- and a big one at that.

"Not having continuity on the offensive side makes it a lot harder, no matter who the quarterback is," Broncos president of football operations/general manager John Elway said. "Unless you have continuity in the system that you have, it's going to be hard to have a quarterback that goes through multiple system changes."

And since Manning exited three years, the offensive statistics, beyond the failed touchdown drives, third-down woes and a struggle to find an identity aren't pretty.

With the pending trade of Case Keenum to the Washington Redskins, Denver will have had nine quarterbacks on the active roster or practice squad since Manning retired who are no longer with the team, and restricted free agent Kevin Hogan will be the 10th if he isn't tendered before free agency opens Wednesday. Rich Scangarello will be the fourth offensive coordinator and Vic Fangio is the third head coach.

Though the ticket-buying public might demand change when times are bad, the Broncos, and ultimately Elway's, constant of change on offense has been a failure. Elway and Fangio haven't been able to publicly discuss their trade for Flacco, who is a 34-year-old and set to enter his 12th season coming off recent back, knee and hip troubles.

So, the Broncos might already have to be planning for life after Flacco before he even starts a game. But after sifting through the good, bad and everything in between, it's clear Elway believes the organization has to find some consistency in what it wants and in the players it signs around Flacco and beyond.

"I've talked to Vic about us trying to make sure that we have the same system offensively and keep that going and be able to hire from within if we were to lose people," Elway said. "But the key thing that we have to do is, systematically, we have to be consistent year in and year out to have these players to get better."

The Broncos have finished 24th, tied for 26th and 22nd in scoring in the past three seasons, respectively, as Flacco will be the fifth different quarterback to start a game for the team since the start of the 2017 season.

It all makes Scangarello, as well as offensive line coach Mike Munchak, two of the most important offseason acquisitions no matter what happens in the weeks to come. Because the two biggest struggles the Broncos have had on offense over the past three seasons is an ability to put a consistent offensive line together and then watching the play of their quarterbacks erode in what often looked like an ill-fitting offense that couldn't protect the passer very well.

In Scangarello, the Broncos hope they get the roots of the Mike Shanahan/Gary Kubiak playbook that Elway says he believes is a quality foundation with the updates from Kyle Shanahan -- Scangarello’s former boss with the 49ers and Falcons -- in the playbook as well.

"I like the offensive background that [Scangarello has] come from, number one," Fangio said. "... I think he's at a perfect time in his career to take on this responsibility. I think he's done it the right way. He went to Atlanta. [He] had a chance to stay there but wanted to go back and call the offense, even though at a lower level (at Wagner College), that he had learned from being in Atlanta."

Munchak, a Hall of Fame guard in his playing career, has long been considered one of the league's best offensive line coaches, having developed high draft picks as well as undrafted players in his more than two decades in coaching.

But in the end it all might have to entail getting something in place and keeping it there, to a position where the Broncos tweak between seasons instead of overhaul.

"I like the system," Elway said. "It's a system I'm familiar with, obviously Mike [Shanahan] started, and Kyle [Shanahan] is taking it to the next level and evolved it. And the success that Kyle has had, wherever he's been offensively. Then to have Rich [Scangarello] study underneath Kyle, I think is tremendous. I'm excited about the system, and I'm excited about them as coaches too. I think that combination, hopefully gives us a chance to be a lot better on the offensive side."