You can just say "I don't want there to be a valid corp path" without insisting that there is no way that a character can ever go down that route in the genre.
Like, stability is a rarity in the genre, and selling out to join into the corp is a valid way of getting it
It undercuts the theme of the genre if selling out leads to a qualitatively better and more stable life. It's essentially saying that selling out is both easy and the right thing to do. Joining the corporate world should be nigh on impossible for an outsider. You should be nothing more than a disposable tool that the corporation mismanages because they don't understand you really and they don't want to.
You don't get to rise up from the streets to the executive suite. Making that possible sends the opposite message of what cyberpunk is supposed to be. There is no path to the top, it is denied to you by dint of class and birth. You will never be more than a tool, and not one they particularly like or understand, in the corporate machine, disposable. And if you aren't disposed of, then that disposability comes into question and the people playing the game will get the message that, well, "what's so bad with corporations anyways? They seem to be doing right by me." And that is not what anyone should take away from a cyber punk setting. That is you just work with the corporations, things will turn out and your life really will be better. So knuckle under and toe the corporate line.
Personally, I think that taking the moral high road and fighting The Man rather than rebelling against him should be less rewarding in material terms.
If being good and just was easier and more materially rewarding, everyone would do it. Taking the moral high road isn't actually easy, and I think a game called "Cyberpunk" should reflect that.
You can get more money and bling.
If at the end the corporation has a bullet put in the back of your head because they've decided your position is redundant.
The ultimate cost for working for the corporations should be made entirely obvious. You have sold out to a system that does not care about your life, and so will terminate it if a spreadsheet indicates a minor uptick in profit for doing so.
Yeah, I don't think anything about a corp path is inherently anti-punk. Just makes it clear that doing so involves giving the boot to a number of people who really don't deserve it.
It should be viable but with very strong "you bastard" themes.
Only if, eventually, that boot comes down upon you as well. There should be no happy ending in the arms of the mega corp, no ability for the player to self delude their character made the right choice.
But seriously, that's exactly the kind of atmosphere it should have.
Too many gamers will get a big ol' stiffy sticking it to poor people. Especially if they're minorities.
No wiggle room, working for the corporations leads to a bad end. Not just ambiguous sadness.