With televisions, computers, cell phones, and other devices constantly and rapidly changing as they adopt new technologies, prices for these devices remain high. LCD is a newer and more expensive technology for TVs, and plasma, being slightly older, is less expensive. In the interest of providing customers with options at a variety of price points, plasma TVs should still be manufactured.
TV manufacturers should continue to make both plasma and LCD TVs, as long as customers continue to purchase both TV varieties. Plasma TVs typically have richer colors than LCDs. LCDs consume less energy. It boils down to personal preference. Give consumers a choice and keep both TV varienties on the market.
Plasma TVs have better pictures but consume more energy than LCD TVs, so, some would argue, TV manufacturers should all get together and make the environmentally conscious decision and stop making plasmas. The problem is there is no way to get all of the manufacturers to agree to this, and even if you could, it would be collusion. If there is a market for a product, someone will build it. If someone is looking to ban a product based on environmental impact, a better first choice would be to go after fuel-hogging SUVs.
People have diverse preferences for the kind of television one might want or need. Some people might not want an LCD television for whatever reason. But, if television manufacturers are beginning to discriminate on the type of televisions being sold, then the consumer really has no diverse choices in the many options available. Television manufacturers should continue to make plasma televisions because they are still a popular and more affordable way to have a flat screen and fit one's needs at the same time.