Responsive design is "hard" as in, it takes effort. It might be worth doing for some sites and maybe less so for others. It's a question of priorities.
The bigger ongoing question is not up front cost, it's maintenance. Responsive design might get you device support across bigger or smaller devices over time without going back to specifically support them, as people are doing now to support mobile and tablet.
We don't know what people will be using even in 5 years... iPad is what only 3 years old?
Not everything needs to be responsive or perfectly responsive, but getting the best experience to your user on whatever platform THEY are on will always be the name of the game (otherwise nobody would support IE 6, 7, or 8).
The bigger ongoing question is not up front cost, it's maintenance. Responsive design might get you device support across bigger or smaller devices over time without going back to specifically support them, as people are doing now to support mobile and tablet.
We don't know what people will be using even in 5 years... iPad is what only 3 years old?
Not everything needs to be responsive or perfectly responsive, but getting the best experience to your user on whatever platform THEY are on will always be the name of the game (otherwise nobody would support IE 6, 7, or 8).