People who seek to become foster carers in a planned way do all their assessments before they are allowed to accept any children. In many cases, they would be asked to start off with respite or short term care to see how many manage before they would take a child for a long term placement. Of course, sometimes short term placements unexpectedly become long term, but usually it's a gradual move into it.
People usually become kinship carers in an emergency situation. So a very brief check to see if a child can go there that night, then a temporary approval for up to 16 weeks, and then fostering panel. During that 16 weeks there's an intense, in depth assessment to go through what it requires, what it means, for the FC to reflect on their own life and this possible life shift. Many temporary kinship carers aren't approved for long term after that 16 weeks because they can't commit to it - it's a huge undertaking - and there's no criticism if that's the case, but it would mean seeking a new foster carer. So there's rarely any opportunity for the kinship carers to plan their lives in advance, but expectation that they adapt their lifestyle over time. I'm not sure why you'd assume that no one would have spoken to the OP about this, that's a pretty strange take and a quick Google would have saved you the embarrassment but there you go.
Kinship care isn't about social engineering to place children with high earners. Someone's finances would be taken into account to see if it's sustainable, but the priority is can they meet the children's needs. Which for children who have experienced trauma and been separated from parents, is stability, time, nurture. The reality is that high earners often have high pressure, long hours, high commitments to the job. Nothing wrong with that, but it doesn't lend itself to being emotionally available to traumatised children, and having a savings account or the potential to pay for university doesn't make up for that. It also doesn't help the carer to try and split themselves in two.