Their absence encourages you to check your phone more often, which means you'll unlock it and look at some content more often, which means as revenue for someone.
Higher end Smartphones have anyway always on displays. And the led needs screenspace - which should be maximized. That's why the notch on phones etc. was introduced.
Sony Xperia user here, I recommend your Next phone should be a Sony. Not only does it still have notification LEDs, it also has an SD card slot and a headphone jack...and a 5500mah battery. Will never go back to Samsung again
I gotta say, sometimes I miss my fully customized LED on my blackberry back in the day. It could be in the bottom of a gym bag and I’d still know if I missed a Google Talk message (green) or a Facebook alert (dark blue) or an email (light blue), etc etc etc.
Off topic a little but I stop most of my messaging app to notify me. And my life is so much more peaceful.
I told everyone when they connect with me on any messaging app that it'll take time for me to answer. I'll read it when I remember to read it, which I do like once or twice a day.
They adapt to that and if it's really important they'll call.
Packaging design, cost, manufacturing complexity, reliability. LEDs require a breach on the case for the lens. This requires a couple components plus sealing plus testing. Affects IP seal rating.
Every physical breach of the case is a reliability, sealing, dust, water, etc issue. Those are the things they fail on phones, after screens and batteries.
The PCB now has LEDs on the edge thdr need special assembly care like the three buttons do.
Most people put protective cases on phones so edges aren't available.
The top is all screen. The bottom sees the desk/table.
Haptics, screen, vibration do so much the loss of the LEDs is pretty minimal.
Don't be surprised if the power and up/down buttons go away sometime soon.
Headphone jacks are a huge problem as is USB and speakers.
When you have questions like this, the answer is almost always money.
For this particular question, it is money - the cost of the LEDs (which is of course minimal, but multiplied by millions of phones), but also manufacturing (need to have a hole in the case to let the LED shine though which can let water ingress into phone). To make those holes water tight would add more cost so instead they decided to use the screen itself as the notification method. I think Motorola's implementation of this was the best - they had their always on display to show notifications and a single tap would let you see what the message was even if the phone was locked.
Modern smartphones hardly have any edges and therefore hardly any space for an LED at the notch. In addition, the pixels of AMOLED displays can be controlled individually, which allows displaying notifications well and consumes little power at the same time.
I'm guessing that with everything they cram into those things nowadays, every last nook and cranny is valuable space to be used.
A little blinken light is probably not high on the list of features competing for that space.
On Samsung phones your whole screen flashes in a custom color and and animation, and after that you have your always on display. So they are no longer needed with OLED screens that can display it themselves
i am still mad they got rid of it on xiaomi note 10 pro.... i mean yhea you can activate a thing for show notification on the screen but slurp slurp the batery. (and future burn in)