Actually @NotDonna , I was in indeed referring to the Level 7 Apprenticeship type leading to an ACA, as that is the route I chose and did. It has always existed in some shape or form.
The posters @Oncetheystartschool and @DelurkingAJ worded it a lot better than I did. Rather than ceiling I should have used the term additional exposure.
What I was trying to put across is that University is a time of personal growth and that period of 18-21 can never be taken back in terms of widening horizons - outside of attaining the profit motive.
Work and Workplace Politics will always be there and it's a long slog to 70, which is worth thinking about in the decision making process. Plus, not everyone in Big 4 wants to or gets to be Partner and there is a whole world out there unlocked by the Big 4 credentials.
One notable thing, is that when the Grads join, they come with a different slant of experience and when they do Qualify, as well as being an Accountant they will have the background of Economists, Historians, Geologists, Pharmacology or whatever their degree discipline was. (Not to mention Alumni links which will be big with his other option of Cambridge in particular.) 'Talking Shop' is important in business and can drive future career options and decisions.
I wonder if this is the reason a lot of the Firms started recruiting outside of the strictly Business and Finance Degrees.
Having said that, it's a wonderful position to be in, having the two options and well done to your son for getting this far. Ultimately, it will be great whichever route he chooses based on his personal preferences and where he sees himself in the future.
It's great you started this thread for him and others to read, as there are very good arguments for and against, to allow a balanced decision making process.