In your world, maybe. Here in Switzerland, 3 months notice is the norm, and six or twelve is not unheard of for more senior roles.
Sure, you could just not show up. But it's breach of contract, makes you inelligble for unemployment benefits, and would result in a bad reference letter, making it harder to get future jobs as well. Oh, and the company would likely take you to court and claim damages.
That said, it is viewed primarily as being in the employee's favor, as the company must respect the same notice period when firing you for anything other than gross misconduct. It often enough results in an employee being given 3 months garden leave (getting paid while at home) after termination. Even if not, the employer is legally obligated to give you a reasonable amount of time (e.g. 1/2 or perhaps 1 day per week) to interview for new roles.
All in all, it's a nice system, at least as implemented out here.