SALES of pc's may have dropped off, but there is NO WAY that tablets and smart phones are REPLACING pc's for naught other than basic functions. The tablet and smartphone will not replace the pc as a true gaming or working platform at any time in the foreseeable future do to the inability to provide the same level of graphics performance, raw processing power, and local storage as the pc has whilst maintaining the necessary size/power consumption/heat constraints to be considered a tablet or smart phone.
The failure of TS 12 to operate properly on the pc has EVERYTHING to do with inadequate programming and NOTHING to do with the capability of the pc as a hardware platform. There are hundreds of applications that place a far tougher demand on the pc platform in regards to graphics and physics than TS12 does, and they are all doing just fine. Admittedly, 3D programming with a healthy dose of physics thrown in is not for the faint of heart, but it's nothing that the current state of pc hardware is limiting. I am certain that N3V WANTS TS to be successful on the pc, but I think they may just be in a bit over their heads in regards to development talent for the direction that they want TS to grow - that's not a bad thing to have high aspirations for your product, but it does require the commitment of sufficient resources to harness the necessary talent.
PC losing it's coherence as a hardware category? I'm sure that real video producers (not YouTube jockies), CAD/CAM developers, music producers, 3D compositors, data analysts, etc are all just laughing their collective arses off over that statement! Sales of pc's to the data-consuming general public that want to listen to music, post to Facebook and Twitter, and send email are slipping. Sales of pc's to people that actually need to get WORK done are still happening. Many enterprises are already moving away from encouraging employees to BYOD because that is resulting in too many unsupportable, inadequate devices such as smartphones and tablets cluttering the enterprise infrastructure while leaving the employee unable to perform their basic job responsibilities. Not to mention the security nightmare that BYOD brought along with it.
N3V could easily take the train simulation market over and make their competitors nothing but bit players if they would just invest in the necessary development talent to keep pushing the envelope.