Why did Menna's Joint on Stadium Drive close?

According to WWMT News Channel 3's Facebook page,

Menna’s Joint on Stadium Drive in Kalamazoo has closed its doors for good. Opened in 2006, the college-style eatery served burrito style wraps called “dubs”. General manager Eric Albin said declining sales led to the closure.

This isn't the first Michigan location to close this year.  the Menna's Joint in East Lansing closed in January of this year after over 15 years hooking Michigan State students up with those delicious "dub" sandwiches.

Menna's Joint website shows the following locations are still open:

Downtown Grand Rapids
44 Ionia Ave. SW
Grand Rapids 49503

Central Michigan University
1418 S Mission St
Mount Pleasant 48858

Grand Valley State University
10897 48th Ave Suite B100
Allendale 49401