There's a myth in product management that states it's a young, not established discipline. Usually, this argument is being employed to justify someone's shitty PM practises.
The first book on product management I've ever read back in 2009 was more than eight hundred pages long and started with the statement above: product management is not a young discipline.
The first product managers have most likely appeared together with industrialisation. As soon as we learnt how to mass-produce products we created a need for people managing this process.
If you take an early industrial production process and compare it with modern product development - you'll see not awfully a lot has changed. We still start with the problem first. Through feasibility and prototyping, we get to an optimal solution. We produce a version of a product and then improve it with feedback. Such a process would apply to a screw or a nail from the early XX century, way up to modern mobile apps.
And when aspiring PMs or their managers say product management is a young discipline they deny the existence of a massive body of knowledge that could be hugely beneficial to them. Good PMs learn anything that could help them to do their jobs better.
Saying "product management is a young discipline" is denying yourself a seat at the table. Why would a leadership team talk on par with someone who's not sure about own functions and values?
Instead, we should be more assertive about promoting good product management processes. We should educate our organisations about the purposes and values of product management. This way we'll be equal partners around the leadership table.