You shouldn't have to upgrade your TV to get an upgraded experience.
With Chromecast, Apple TV, roku and the ilk, think of your TV as only a panel. You want a really really good panel and then be able to upgrade your TV experience out of band from replacing that panel - ideally spending $35/year at most.
I own a 1080p "LED" LCD from LG that I bought in 2011 for $400 - a great panel and has no "smart" features. But, totally worth it, especially thanks to Chromecast (and Plex) today.