Nah. They used to flash different colours for different events, and you could filter what created an LED event. Even with the OLED screen, leaving the notification/clock on all day drains the battery noticeably more than having it disabled. I find it better to only have that on at night when charging. Not to mention you didn't need to look at the screen. You'd see the flashing light and know there's something to check.

But, what they COULD do is simulate a series of LEDs properly with OLED. That should in theory take a similar amount of power (for the screen at least) as a real LED. But, I suspect driving part of the screen would require the screen controller active. I suspect the older phones with LEDs had some separate low power driver storing the most recent events from when the phone last "woke up" using minimal power for the flashing LEDs.

So, in all it genuinely is a missing feature that has no equivalent in modern phones.