As we hit the final stretch of the MLS regular season, all 20 coaches in the league have kept their jobs. It's a level of job security that raises serious questions.

When considering the most secure jobs in North America, you wouldn't automatically think of coaching professional sports as something that should be on the list. If anything, coaching pro sports is one of the most tenuous professions there is, with pink slips seemingly ready to be dropped at all times.

Not so much in Major League Soccer though. At least not in 2015, a year that has seen all 20 head coaches navigate through two thirds of the season without a single coaching change. Yes, you read that right. Not a single coach in MLS has been fired, or quit, as we head into the final stretch of the regular season.

How does this happen? You can blame it on lethargic ownership groups, and a new playoff format that gives 12 teams places in the playoffs. You can also point to the inordinate number of former MLS players who are coaches now, men with long-standing ties to the league and, in many cases, to the teams they now coach.

One reason for this anomaly of a season is the fact there are a handful of teams that have committed to young coaches and are riding out the inevitable growing pains those hires were destined to endure. Both Philadelphia and Colorado have posted disappointing results, but Union coach Jim Curtin is in just his first full season while Pablo Mastroeni was a legendary player for the Rapids and has the long leash to show for it.

What makes the perfect 20-for-20 stat even crazier is the fact that the last coach to be let go in MLS was a coach with a very successful track record. Mike Petke won a Supporters' Shield and came within a game of the MLS Cup final during his two years in charge of the New York Red Bulls, but that didn't keep him from being forced out by a club that was planning to make changes in the wake of Thierry Henry's retirement.

It is tough to argue with New York's decision now. Jesse Marsch has worked wonders with the Red Bulls and currently has them playing some of the best soccer in the league, with a fraction of the salary budget the club spent in previous years.

The Red Bulls made a tough and unpopular decision, something it seems not many MLS teams are in a hurry to do. In fact, it seems as though teams aren't in a rush to make any decisions at all.

Real Salt Lake is an exception. No, the club hasn't fired head coach Jeff Cassar, but this week owner Dell Loy Hansen forced out president Bill Manning in what has been the only major front office change we have seen in the league this year.

There have been no such moves in places like Chicago, where the Fire are in the Eastern Conference basement after completely overhauling their roster last winter. Nor have we seen a shakeup in Colorado, where the Rapids are set to miss the playoffs yet again.

Just how many coaches should have been fired in MLS by now? Coming up with an exact number isn't easy, but it's certainly greater than zero. That number surely lends credence to the growing sentiment outside the U.S. that MLS is a low-pressure league. There is little doubting that the quality of the league is improving, but as we hear more former MLS players (usually foreign players) make public comments about the league's lack of pressure to perform, it becomes tougher to ignore.

Nobody should be clamoring for the kind of coaching instability found in places like Brazil and Mexico, where the carousel spins consistently with new coaches, but the other extreme isn't an answer either. Job security has always been something coaches in MLS enjoyed more than most leagues, this year has taken things to a new level.

The current MLS coaching anomaly became even more glaring on Friday, when NASL side Tampa Bay Rowdies fired head coach Thomas Rongen. The popular coach was let go after the Rowdies endured a rough run of results during the NASL fall season. It mattered little that the Rowdies finished second to the New York Cosmos in the spring season, or that Rongen had helped the club secure several high-profile talents. What mattered were results, and the Rowdies had endured a terrible run of results. That was enough to convince owner Bill Edwards that a change needed to be made.

As much as Edwards' decision can be criticized given Rongen's track record, Edwards made it clear that results matter, and he made the kind of decision that we see made everywhere around the world.

Everywhere except for MLS, at least this year.