Sadly 'we' (this is a global 'we' in relation to english language tv entertainment in general) just don't know how to (or are simply not able to) make good TV shows anymore. Sure we get the odd fluke show that gets it right (i still enjoy The Big Bang Theory for example), but i honestly have not been able to watch and enjoy any of the main channels TV series for over a decade now (from the BBC, ITV etc).
Science and Nature stuff is still decent quality (Brian Cox, David Attenborough, etc) but the last time i was able to watch a whole 'entertainment' series we are talking way back (Doc Martin might be a rare example of a long running show that did not lose it's mojo). 'Day of the Triffids', 'Threads', 'Space 1999', 'Blake Seven', 'All Creatures Great and Small' etc etc. That was really the golden era of TV's entertainment shows, where good writing, good acting and good production teams knew how to tell a logical tale with 'real' characters and interest.
I blame 'Big Brother' (the tv show) and that era of TV where the rush to the bottom has spread it's influence into everything else. 'Quality' is the rarest of commodities in TV these days imho. So much so that even when something 'historical' is attempted ('The Tudors' for example) it just bleeds modern-day thinking to distraction that you can't actually believe these people are doing what their doing and saying what they are saying in the historic context, so it becomes a strange make-believe rather than historical re-enactment. Shows like that, that we make today, would totally not surprise me if the 'Henry V' character in it suddenly pulled out an i-phone to gossip about sex lives with the 'Cardinal' or something.
And it is much the same for film also (see Star Wars after the orginal trilogy etc).
We are just way past our creative best as modern english speaking nations, it's all about the ratings and viewer numbers and the dive to the bottom common denominator. It's destroying our 'culture' in effect.
It's got to the point where i won't even bother watching something like this new War of the Worlds series as i know before hand not only is it going to stink, but it will likely ruin what was good about the original sources it was based on.