First, most churches don’t even have a lot of Ordinary Ministers. Most churches have a priest, and probably one deacon (although I’m thankful my small Southern church has two priests and three deacons). Not every mass celebrated has a deacon present, so in many cases, the only Ordinary Minister actually ministering the communion is the priest himself. If there are two lines of laity to receive, that’s three (if Blood is distributed) EMs to be had. Clergy shortage. It’s not fun, but that’s the way it is right now.
Second, part of our “modern Catholic” mindset infecting our church right now is a perversion of the call for more “active participation” of the laity in mass. The use of 8 EMs for a Sunday mass is part of this sad truth. People don’t realize, unfortunately, that “active participation” is as simple as actually absorbing the prayers, music, and silence of mass. They think that they have to “do” something to “participate,” as if it’s a field day or a school play or something.