Disagree, many companies have a way for engineers to pivot into product. The hardest part is having a frank conversation with your manager. I’ve seen many engineers become PMs within the same company
I'll share my experiences becoming a PM outside of a formal program like APM. I started out as an intern and now I'm a junior PM.
You're slightly moving the goalpost with your comment, because it's not necessary to go through formal training to be a PM. Engineers are tangentially involved in the product process pretty much always. The transition is essentially about taking more responsibility over the product and spending more time driving product vision as opposed to building. Passing a PRD to your manager if you thought a feature could be done better was encouraged at my last job.
Your manager will often support you doing this. Then, if you've been doing this well, you can speak about making a change to the PM role because you've proved yourself. If your manager does not support you doing this or the company doesn't need another person in a product role, then you might need to make a change.
FYI large companies accept internal applications for their APMs, which is a formal training program, albeit pretty much for junior employees only.
