I think the three class system is still very much alive and kicking. You need look no further than the present 'government'....J Rees-Mogg for example!
He’s in a Class of his own (and not a good one)
The threshold for students who have graduated recently is £27,295. Median graduate salary is apparently £25k according to https://www.hesa.ac.uk/news/16-06-2022/graduate-outcomes-data-statistics-201920
So half of graduates won’t be earning enough to start repaying immediately.
The next aspect is that repayments are means tested, you’re only paying 9% of salary above the threshold. So it’s not like paying off a normal loan where you have to find £X every month regardless of salary. It comes off automatically so you don’t have an issue where you‘ve already spent it before it’s due.
The student loan doesn’t appear on your credit file, so it’s not a debt like others. The only aspect that will matter if applying for a mortgage etc. is when they ask about monthly outgoings to check affordability it will be there.
also for any students with loans up to this year, they are written off after 30 years, regardless of how much has been paid back.
For students from this year, that becomes 40 years.