Steam will help you play any game in VR
SteamVR's Desktop Theater Mode makes 2D games playable with a headset.
Sure, SteamVR is making it easy to play virtual reality games. However, you probably have a whole bunch of conventional games in your Steam library -- what about those? Don't worry, you're set. Valve has unveiled SteamVR Desktop Theater Mode, which lets you play any Steam game in VR. Ultimately, it boils down to putting your games on a big, simulated screen. What it looks like isn't clear yet, but it should work with the HTC Vive and any other SteamVR-friendly headset. The Desktop Theater is in early beta testing now, and will get a proper debut at the Game Developers Conference next week.
It might be a necessary move. The odds of many game developers retrofitting existing titles for VR is pretty slim, and there will be certain games that just don't make sense in an immersive form. This gives you a way to switch Steam games without having to repeatedly remove your VR gear -- you can keep it on for as long as you're playing games (and if other developers have their way, beyond that). Moreover, this gives you a reason to buy that pricey headset beyond the handful of VR games available at launch. It might just help you concentrate on your game by shutting out more distractions.
