Two DC I can cover.
A combination of CTF supporting their first year (small monthly savings since they were born adds up)
Their own savings from part time jobs since they were 16. Has this impacted their studies? Possibly. Has it given them confidence and an understanding of how badly retail workers are treated? Definitely. Do they have jobs to return to in holidays? Yes.
Savings I will make on food, travel etc when I have one or two less children at home. I eat a lot less and simpler without the kids, I turn the heating on less, use less hot water etc.
Supporting four DC through uni would drown me. Their individual CTFs would be smaller (or non-existent), I would have spent more time out of the workforce and earning less income, they probably would have had to use more of their part time wages for day-to-day expenditures, if one DC was at uni, I'd still have 3 at home using utilities and eating food, etc.
But (aside from multiple births) the number of DC you have is a choice and it's pretty obvious that the more you have the more the cost.
I hope people with young DC are reading these types of threads and beginning Uni savings early, and also considering the cost of uni when deciding whether to have the third or fourth child.
It's very expensive, the system for support isn't the fairest, though it's hard to think of one which would be fair to all, and the financial side takes approximately two decades to prepare for 🤷♀️