Plastic don't rot.
Plastic don't die.
Plastic ain't sensitive to water parameters.
Plastic need not defend itself from herbivorous creatures.
Well, based on an argument like that, sounds like plastic fish is the way to go too.
Live has the potential to look this good.
and fake dont
Sorry, but no, they don't. Just my opinion, of course.
Despite the talk you hear about lots of fertilizers, blinding amounts of light, and industrial-strength CO2 injection systems, it's usually quite easy to successfully grow plants without all of that ...
provided you do research, and choose plants suitable for your conditions.
Just as an example (and not to pick on tempestuousfury), it's not surprising that someone would have trouble growing mondo grass. Mondo grass is not a true aquatic plant -- it's not meant to grow completely submerged, so it's not surprising that it dies. Unfortunately, some pet stores "feature" terrestrial plants in their aquatic plant selection. Prior research is your friend, and time well spent.
Similarly, if you go out and get some rotala, glosso, and Eusteralis stellata, and toss them into a tank with only the single light bulb that came with the tank, they're almost certainly going to die. However, if you do some research, and decide instead to pick up some java fern, a crypt or two, some hornwort, and a couple of anubias, you'll probably find that your plants are doing well without you even so much as looking at them.