While *maybe* there are more TVs than computer monitors (personally I have a 2:3 in my house - 2 laptops and one desktop vs 2 TVs), there are far more mobile displays with far hight PPI than the crappy TV one.
Full HD is actually low res, adapted to a world of low bandwidth cable or aerial transmission.
What happened to computer displays in the past decade - specially laptops - was regretable. The rather bad 16:9 AR, low rez displays and 15.6" glossy displays
This is actually the only think I do trully appreciate about Apple.
We should be at far higher PPIs (and I still prefer the 16:10 AR). Problem is that not even the software helps (OS support needs to improve), so that a 3840x2400 24" has decent sized images (text in particular).