The few times I've found myself on the IRC recently, I've noticed that some of the members do stop by occasionally. It's just a matter of when people actually have the time for it - which me and several others here rarely seem to have anymore.
I don't always have time to get on my computer, unless it's for classes. Other times, I'm not likely going to be sitting still for a long period of time.
I don't think there's any reason to hate Telegram over all of this: it isn't necessarily "replacing" IRC (at least, I don't think it is?), it's just easier for most people to access and keep up with because it's on phones. I'm able to check it more often because I always have my phone with me. I'm not using it in place of IRC, I'm just not using IRC as much as I used to (nor as much as I'd like to).
Even then I don't message on Telegram everyday, I just check my phone to see what everyone's saying and occasionally type a message. It's pretty much just one big group text message to me.
Not trying to speak for the whole group or anything, but that's my thoughts on whole thing. ;[