London's developers are hell-bent on snapping up the best bits of the city for the wealthiest clients, and the government doesn't seem very motivated to protect them for public enjoyment.
It's pretty frustrating as a citizen feeling that no one's got your back - the rich and the powerful work hand in hand for their benefit and everyone else is left with the scraps - little bits of fenced of public space as a charity gesture for the people who made the foolish choice of not being filthy rich.
While I get how it must be tricky for Londoners to escape the chaos for a few hours, the UK is a tiny island and you're never more than a short train ride away from countryside.
Depends how you're defining "countryside". If you want to go to a large unmanaged forest, tough, there aren't any (e.g. Epping Forest is nice but it's too narrow to get lost in). If you want to go up a mountain that feels like an actual mountain, you've got to go over the border into Wales or Scotland. In all these cases you'll rarely be far from a village.
That doesn't address the political and social issue though: who is a the city for? Who should have access to public space?
I believe that in a crowded city it's really important that things like parks and riverbanks are accessible to everyone. Otherwise you slowly create a city of gated communities, a two-tier society. Saying "you could go somewhere else" is basically admitting that the city is becoming unlivable to the common man.
It's pretty frustrating as a citizen feeling that no one's got your back - the rich and the powerful work hand in hand for their benefit and everyone else is left with the scraps - little bits of fenced of public space as a charity gesture for the people who made the foolish choice of not being filthy rich.