According to Daniel O’Brien, HTC's Vive General Manager, HTC Vive version 2 will be coming at some point but when that happens is going to depend on innovations and advancement in technology. O'Brien reportedly said in an interview that the company is not going to pick a production cycle or timeline. HTC is focused on "bringing really meaningful innovation" to the VR experience and to help create completely new experiences. O'Brien went further still, referencing the feedback the company has been taking about their current generation Vive headset and the directions that developers would like to see improvements take. For O'Brien, "that’s how we’re solving the next headset" and it will come to market when substantial innovation can be brought with it.
Many people expected HTC to reveal the second generation of its Vive VR system at CES 2017 and that didn't happen, but that doesn't mean the company hasn't been thinking about it. HTC's first-generation Vive headset has already had several upgrades and there are upgrades or accessories available for the system that include things like lighter cables and a room tracking system. There's also now a completely different line of Vive-branded headsets aimed at the enterprise market. The "Business Edition" Vive comes with several perks of its own. HTC seems more than content to provide add-ons where possible to give owners new features. According to O'Brien, it will take something like a meaningful advancement in screen technology or in some other area where an add-on just won't do the trick. O'Brien also hinted at what will most likely be another accessory to come in 2018, citing HTC's involvement with a Vive X company called TPCast. That, he explained, is a wireless add-on. He went on to posit that, at least for much of 2017, wireless is just going to be something that's optional for most people but that by 2018, it is going to be expected. As a General Manager in HTC's Vive department, that does provide some insight into how the company is approaching its VR headset system.
That said, HTC seems to be approaching VR from a marketability standpoint - focusing on feedback and market trends, while fighting traditional product lifecycle expectations. Hardware often has a finite lifecycle due to the limitations of components that make up a given piece of technology but, for areas of technology that rapidly advance, those can be shorter if previous iterations become unusable or obsolete due to new innovations or market expectations. HTC's representatives have reportedly said before that for VR technologies, and specifically for high-end PC-based VR, the expected lifecycle could be somewhere around one to three years. However, given the timeframe, O'Brien's abovementioned statements about 2018 and wireless could also be indicative as to when HTC will move on its next-generation headset. Until HTC comes right out and says so, or suffers significant information leaks, it's probably best to simply bet that it's something they're working on.