Complex sentence: In each town, a megaplex would often put the town's smaller theaters and even multiplexes out of business, and were often coupled with other big box stores that were reaching their zenith at the time.
Split into simpler sentences: In each town, a megaplex would often put the town's smaller theaters--even the multiplexes--out of business. They were often coupled with other big box stores that were reaching their zenith at the time.