Every once in a while you'll see consecutive win streak for superclubs across the world. Because of social media, it may seem like a more common occurrence than it is, but it does seem to happen much more in open leagues.
In MLS, consecutive wins = pure evil. Why? The theory is that team parity is a key driver in interest in the league. Simply put. If your team sucks, nobody shows. For the most part, this is true. Especially in a closed league. You HAVE to have some hope year to year because there is no chance at glory in the league you drop down to.
There is also a business reason. Well, not also. Business IS the reason. Here, you can't have chronically underperforming teams when you are sharing revenue. A poor performing team in key revenue/interest generating areas (example: Chivas USA) becomes an anchor to the other investors.
The Chicago Fire are in this situation right now. They are not an asset to MLS. They should be, however, so the league is placing the annual MLS industry meet and greet they like to call the all-star game at Soldier Field.
All this said; Outside of the fact that MLS controls player contracts, it has dozens of rules in place to ensure teams do not get too good or too bad.
Here are all the teams since 2000* that have managed 6 or more wins in a row >
Consecutive Wins, Team
7 : Sporting KC (2012)
6 : New England Revs (2015)
6 : DC United (2007)
6 : DC United (2006)
6 : Miami Fusion (2001)
6 : San Jose Earthquakes (2005)
6 : New England Revs (2005)
*There were no draws before 2000.
What's interesting here is that we don't even have to look up as to why these teams somehow managed a nice run of form. Starting from the top - KC... new ownership, completely new rebrand and new stadium. It was a huge win on and off the field for them. The momentum has been sucked away, though. 2015 Revs signed Jermaine Jones. That's basically it. In 2005 they had Clint Dempsey. That Miami team is basically a who's who of MLS now. Current RSL coach Jeff Cassar, Kyle Beckerman, Brian Dunseth, Preki, Nick Rimando, Pablo Mastroeni. The DC team also had Rimando one year and Perkins the next, but were lead by Ben Olsen (current coach), Bobby Boswell, Jaime Moreno and Christian Gomez. The 2007 added Greg Vanney (who now coaches in Toronto).
Columbus hasn't managed to win more than two in a row since the end of 2014.