Well, there isn't much requirement to study Eng Lit boschy - the gateway GCSE is English Language, or English, & there's absolutely no reason for any moderately intelligent, hardworking, well taught 16 year old not to get a grade C (unless they're being used as a political football, as last summer, obviously...).
Eng Lit's a different GCSE - increasingly restricted to higher ability students as we teachers have to game the system, sadly.
GCSE Eng/ Eng Lang measures an ability to understand & use language which is fairly crucial to further academic study. It's certainly demanding, but it really should be something most students are able to pass if they are decently taught & work hard to hone the necessary skills.
If you don't manage it then yes gateways start closing - two out of three of our local sixth form colleges won't have you for the vast majority of their courses without a C in English.
It's a bit stark, I know, but their experience is that if you can't pass English GCSE despite working your butt off, you're unlikely to cope with A Levels, whereas if you are relatively able but failed because you chose not to do any work at KS4, they'd sooner give their over-subscribed places to someone whose track record suggests they'll make good use of the opportunity.
Last year I had 60 borderliners who were either 'strivers' or 'able but idles'. Based on the previous year's grade boundaries, all but half a dozen would have been OK - once they were mucked about with, another 10 came out with Ds.
Now you could certainly argue that one way or another these were not especially academic kids, & that they should, from the outset, have been funnelled down a different pathway from 'go to college & do A Levels'. But the way the rug was unexpectedly pulled from under them was cruel.
I ran into a couple of them in CEX the other day. Nice to see them smiling & enjoying their summer - I remember the tears this time last year only too vividly.