Even the "correct" examples are often incredibly bad.
A choice between two actions, where the action that most people will want to take doesn't look like a button and more like some misplaced text, while the option that people will only choose by accident is prominent and a proper button? The styles aren't even consistent. Like having a steering wheel only for left turns and a lever for right turns. Utter nonsense.
Can you provide an example of two primary button stacked near each other in a good design?
It's not about which action is highlighted and which action is not, it's about not having two primary action near one-another which goes against any UI/UX theory and best practice
What if both actions are equally valid? What does UI/UX theory say about that? Honest question here. I see how having two primary buttons would look ugly, but inducing the user to pick the choice they didn't want (because they were just pressing next and didn't stop to read the "skip" button in the small print) seems even worse UX to me.
Two primary buttons stacked is just awful. I agree that transparent secondary buttons have issues, but two stacked blue buttons is pure shit so an easy choice.
It is shit because there is no such thing as two things being primary. It is perfectly okay to highlight the default choice, or not highlight any option, but having two default options makes no sense.
A choice between two actions, where the action that most people will want to take doesn't look like a button and more like some misplaced text, while the option that people will only choose by accident is prominent and a proper button? The styles aren't even consistent. Like having a steering wheel only for left turns and a lever for right turns. Utter nonsense.