> However, in "engineering" type of software products (game engines, RDBMS engines, operating systems, etc) where the software is more often a "product" that's sold (aka profit center) ... there are definitely different layers of complexity where senior and junior engineers are not fungible at all.

That's great and all, but that's a small minority of all software written. I'd love to work on projects like that but ultimately I have to pay the bills. Many software engineers are in the same boat I am.

Now I guess I'm just up shit creek because I built a career on SAAS work that was available instead of holding out hope I could get in at my dream job working on game engines or some other non-SAAS product?

Sorry if I sound bitter. I'm variations tired of hearing variations "If you only worked in SAAS you were always close to meaningless and now we've automated you so you don't deserve to earn anything anymore". Feels like every day.