A few misconceptions here.
The person on £100k owns their own home, that’s safety and security for life.
A mortgage isn't owning your own home, and safety and security for life. Yes – it's the more secure of the two, but it's only 'your own' home' as much as you can make your mortgage payments. High earners are at more at list of redundancy, as when companies restructure they strip from the top down. It's also harder and takes longer to secure another position at that salary level. Doing so can also very often mean more and more expensive travel.
Probably retire before state pension age
Perhaps if they are already mid 50s, and likely older. I know many people on £100k+, from mid 30s to late 40s. None of them are on track to retire before state pension age. Only one is, but he is on £300k a year. People are having children and getting on the housing ladder later and later, meaning that their earning have to stretch much longer now.
If they have kids they’ll have been able to support their kids through education and early adulthood and see them set up for life.
Absolutely not true for anyone I know on £100k+. Most of their earnings are going on nursery and wraparound care for all the school and nursery years, which sets back savings as awful lot. Most are more able to support with university costs, but 'setting them up for life'? No. Again, perhaps if you are one of those people in the top 2-5%, but not your bog-standard £100k earner.