On the job training is very much a thing, but I think the vast majority of companies out there prefer to start doing that while a potential hire is still in col

On the job training is very much a thing, but I think the vast majority of companies out there prefer to start doing that while a potential hire is still in college. It's less risky and usually the potentials are more moldable. Internships that move to a full time hire is how we brought in a large percentage of the workforce over at Microsoft, and the same is true where I am now (Atlassian). For those in that position, we supplement their internships with a lot of on the job training. It becomes harder when someone is in the position you're in - 4 years of experience at companies that aren't big name ones. Most companies aren't sure how good your skills will be, and you come with way more risk than someone still in school. If an intern doesn't work out, after six months you just don't extend them an offer. Their internship becomes a long extended interview. In your situation, if you pass the interview but don't end up working out after 6 months, the process of removing you is much harder. It requires a lot more risk on the company's part, so almost all of the big names exclusively look for college hires.