Since we are speaking of reasonable people, most reasonable people would define "corporate media" as for-profit entities either privately owned or with shareholders and which rely primarily on advertising to turn a profit. Nothing in that definition defines PBS or NPR as "essentially corporate media". What you are probably angling at is corporate underwriting -- in which case I can only direct you to read their statements of editorial standards and independence found on their websites. Now I suppose you will have to take their word here...but if not, then it's just an endless rabbit-hole of debate.

Now I won't say PBS or NPR are above criticism -- and as the kids say, "there's a lot to unpack here", but let's be honest, is NPR's journalism really low-quality? Or is it more likely you have a bit of grievance with NPR because you feel they do not favor your own particular political bias? Since we are internet strangers and have little context to go on, I can only assume the latter is the most likely.