High credit card limits are often earned over time. Start modest, accept increases, have higher limit.
Asking people to say what limits they’ve got takes no real account of what lenders have as criteria for different customer segments.
It’s possible that one customer with, say, a £10k Halifax limit will be offered a tiny amount by another provider on a successful card application. Another customer may get a similar limit to their existing big limit card because the new provider sees their credit file as an opportunity to get significant low risk spend.
Me? Half a dozen cards with limits all over £5k. Balance typically under £200 a month paid in full. Rarely used cards seem happy to keep me on the books.