No, the SAK is still Ctrl+Alt+Del, and it never went anywhere. (It never was a technical requirement for logging in, merely a policy decision.)
On "consumer" versions of Windows, the SAK (Secure attention key) requirement was disabled for convenience, although can still be enabled via Group Policy, or even via
control userpasswords2. Server editions still have it enabled.
The SAK still remains useful – when logged in, you can press it to get the "Windows Security" screen, change your password, or start Task Manager. So it can still be used to manually verify the login screen, even when Windows does not require it.
You cannot make every key be a SAK, because that would make it impossible for other programs to react to keypresses (which is the whole point of a SAK).