The point of the current system is that the state and the church legitimise each other.
The contrary argument is that they now de-legitimise each other more than vice versa. The Church makes the state look sectarian and not inclusive of the racial/religious diversity that is "modern Britain", and the close association with the State makes the Church unattractive to the majority of the young who are alienated from, or at least disinterested in, anything to do with the state. (It also makes the Church unattractive to the fundies who disapprove of Labour equality policy etc.)
Where I do agree is that if the official CofE imploded, it would more likely than not be replaced by a plethora of even nuttier sects and Churches. Those who are most critical of the establishment churches are often even more credulous when it comes to the nuttier varieties of same. notes from no w here
So they're already beyond reach.
It isn't seriously interested in inclusiveness, either. (Clearly.)
The legitimisation is entirely ritualistic. The CofE is really one of the last remaining links and relics of the Empire. Losing it would mean a final admission that the days of empire and immense significance are over - at least among the Westminster, shires and Belgravia set who care about these things.
The oiks elsewhere are hardly relevant in this, even though they happen to form a popular majority.
The CofE hasn't been seriously interested in young people - unless they're in a very narrow band of middle-class youngness - for at least fifty years now.
From memory, I'd underline "at least".
I also agree that disestablishment would be the end of the CofE. The strands of Low Church Evangelicalism, Middle Church stodgy conventionalism, and High Church Anglo-Catholicism (to simplify) have only held together over so many years thanks to the snob-appeal tradition of the ancient established Church. A few Evangelicals might peel off towards Nonconformist Evangelical denominations (but mind the steps, you're going down the class stairs rather fast), and a few spikies might turn RC (no social decline there), but by and large Anglicans hold on for prestige reasons. A disestablished CofE in which each local church would gain autonomy, would pretty soon lead to a break-up.
