First off they are not 4 months old. They are likely 14months or older.
Peppers are actually perennials not annuals. They can grow continuously until frost or disease kills them. Many greenhouse operations try to keep them growing for 1.5 to 2 years. Those large plants are highly productive.
Virus infection like TMV is the most common reason they have to dump a greenhouse.
well this is what I wondered. Look at the size of the trunks. This isn't the breed of chili peppers they sell for home gardeners for sure. Its growth habit is to grow tall for commercial pickers.