Life is undoubtedly easier if you fit in the box, do lots of GCSE's and then A levels, and get great grades. If school fits, and you fit school, free school, that's easier all round. One of mine is exactly like this and will come out with amazing grades.
Not everyone, indeed probably the majority, are going to tread this path. Lots of parents are not engaged and do not do extra trips to museums or NASA or whatever- the person who listed the skiing trip and trip to NASA at their school, great for you- these trips are 100's or 1000's of pounds and most ordinary people simply won't be doing these trips or anything like that in their time in state education. Money talks, and you can pay your way to get a reasonable education out of state education by paying for the extra trips and the tutors, but that's not what's on offer for free, nor what most can access.
I am not a HEdder currently, and I agree state education is the best option for lots because their parents couldn't provide high quality alternative provision. Some of the things stated on this thread though are blatantly untrue about blocked careers, unable to access university, and so on. It's important to challenge these because others might be desperate, have a child who simply can't or won't get on in state education or doesn't have enough provision for SN and think their life chances are ruined for ever if they HE. This is not true. I would not recommend withdrawing them from getting qualifications, but this can be done in different ways and not always is best done by going to the local comp where not all the teachers are specialists or the teaching stable at all. Nearly 50% of students do not get the A-C 5 grades (or their levels in numbers as it now is) to go on to higher education. Nearly 50%. So- are these pupils well served by current provision?
I have a horrible suspicion that it is the parents that make all the difference, and that's why HE works well for engaged intelligent parents with money, and school works best for engaged intelligent parents with money. There are some schools that can compensate for this by being brilliant across the board, but most are not able.