For the people who get into psychology-related careers, their psychology degree was probably not the main reason why. That was just the minimum requirement.
I'll talk about 3 people I know who got into it.
Person A works as a mental health professional/clinical manager. She graduated in the mid-late 2000s with a psychology degree from Bangor - not the most prestigious university but a good one nonetheless and it's fully accredited. Whilst doing her degree she worked part-time as a support worker/carer in a mental health institution. She leveraged this experience to get a graduate role as a mental health practitioner and has risen to become a clinical manager. She needed the degree in psychology to be eligible to apply for the role but the experience is what won her the job. Lesson = a psychology degree on its own simply isn't enough.
Person B got his first job out of university working for the prison service writing psychological profiles of inmates. Not sure of his precise job title. He attended Edinburgh University, graduating in the late 2000s. He was highly academic and specialised in forensic psychology as part of his degree, doing his dissertation on this. He made a lot of contacts doing this and developed specialist knowledge that was highly relevant to the role he applied for. He had a lot of generalised work experience outside of his degree where he was working with the public. In his case it was the specialist knowledge he had gained and his understanding of the workplace environment that made the difference. He was also highly personable, confident, with a good deal of experience of life outside of his specialist field - a good all-rounder. He might need a master's and maybe a published article to warrant the same job being given to him now but maybe not.
Lesson = it's more than just the basic degree. You need to bring something extra sometimes to get the right role.
Person C did a specialist conversion degree with a strong track record of getting its graduates into professional doctorates. She was a former SENCO at a school with three years experience directing the special educational needs programme and working with psychologists, SLTs, OTs, PTs and parents as well as the children directly. She is now an educational psychologist.
Lesson = you can't always plan a career in psychology. Sometimes, the people they want to do the job are not the people with the degrees in the subject. Psychology graduates are not going to compete with those people. She was taken on because she knew the job, knew the environment, understood the role, knew how to work with the client groups and the other professionals she would be working with. The conversion degree was just what she needed to be eligible to apply for it.
Psychology degrees are good degrees to get but you've got to be realistic about what the prospects are at the end. Your experience counts more than the degree a lot of the time. I could have cited a whole other set of people with these degrees who are woefully underemployed right now, despite having prestigious degrees from various prestigious institutions. I know a lot of people working in mental health who have no degrees in psychology but they do have degrees in mental health nursing. They're what the NHS actually needs. If you want to work in mental health, do psychiatric nursing. Good way in to a lot of roles. People don't want to because they think they lack prestige but I know a fair few people who are qualified CBT therapists, psychotherapists, even now clinical psychologists all off the back of doing a degree in mental health nursing.