I think you will find that private schools, selective schools and those comprehensives with a largely middle class aspirational intake will not have made languages optional, realising that a quality qualification in a foreign language will be viewed particularly favourably at any future university selection interview.
Whereas those schools in more challenging circumstances will have dropped languages like a hot potato seeking to shoe-horn as many people as possible onto far easier applied GCSE courses in the pernicious and educationally destructive race to compete with the headline A* - C figure of the more privileged schools previously mentioned.
In addition, like maths which is also taking something of a beating as a subject at the moment, you overlook the difficulty of the subject in the context of the ever-diluting nature of the rigour of expectation of the curriculum. Indeed, the gaps are there before GCSE.
Look at the KS3 Shakespeare paper and what is required to get a level 5 and above without any real knowledge of Shakespeare plays and compare with MFL where you have to be proficient in all skills, including writing, in two or more tenses. Even to achieve moderate success at GCSE you need a huge knowledge of vocabulary and structure.
I remain passionate about languages and look forward to whatever the future may bring but let's have a deeper look into the issue and it would be nice for once to operate on a level playing field in the difficulty stakes by cranking up large parts of the curriculum or making MFL easier. Graham Smith West Yorkshire