You would have to further define "sucks" for me to elaborate further.
In most cases I've seen, people are doing the best they can with what they have. Large churches have the luxury of choosing the picks of the litter, or going with hired guns. They can then have a highly technical, elaborately complex and polished sound with lots of intruments doing lots of fancy things.
Smaller churches rely on volunteers of varying and sometimes very limited skillsets. For example since I moved over to guitar/worship leader from bass, our replacement bass player has only 9 months experience and I sometimes still have to map out songs for him chord root by chord root.
It's not really about entertainment or catchy tunes however, it's about worship. The praise and worship segment of a church service is supposed to be just that, Praise and Worship. To do this, the congregation has to be able to participate.
We've tried some complex songs before, which had cool intros, flashy turnarounds, slick instrumental breakouts...and we simply lost the congregation. They might be able to clap their hands in time or something, but they were'n't really worshipping. They do best with traditional hymns that they grew up with, and praise songs that they can learn relatively easy and quickly be singing themselves, which is in itself, a form of worship for them. We are not there to perform for them. Much of the music I play, I would probably never listen to in my car. A lot of it is repetitive verse chorus verse chorus tag stuff and the verse may be even be the same one over and over. In service however, this allows people to not worry about trying to remember what they do when we DC Al Coda to another section of the song, or do a fancy instrumental bridge etc.. In true worship, sometimes the KISS principle is truly best.
An example is the song linked in my sig. This would probably be considered pop-rock simplicity of no real theological significance. When we kick off a Sunday night service with it however, you can see/feel/hear the joy and energy in the people and it carries over into the subsequent songs that follow and even into the reverent hymms that lead into the sermon.
The funny thing is, no matter what kind, style, tempo, characteristic, level of complexity of music we've tried, at least some portion of the congregation has found it:
Too fast
Too slow
Too traditional
Too contemporary
Too complex
Too simple
Too theologically deep
Too shallow
Too loud
Too soft
Too instrumental
Too vocal
Too...insert adjective here.
It's simply the way it works when you gather people of varying backgrounds, heritage and taste. We just do the best we can.
Here's a funny read:
Worship Styles