Even tough I use copilot on a daily basis, I don't really miss or notice it's miss in environments where this isn't possible. I guess it hasn't replaced my skills built over the past 20 years.
They made ChatGPT even for premium users relatively useless. I made the same experience, that it did a very good job on many things shortly after release, but now the answers seem very flat. But I can certainly see why, regarding how many people are flooding their apis with requests. I just hope that in 10 years we'll have mobile hardware capable of running gpt4 sized models efficiently.
Edit: They definitely didn't make it useless.. It's still a very impressive technical achievement, since it can even browse the web and run code for you by now.