Because of my work I get to (more like have to) deal with tech from 20-30 years ago, but also tech on the bleeding edge. Seeing SDH systems from the 2000s serving a couple legacy 2Mbit lines right beside state of the art VPLS service routers (on that note, we got some that have bluetooth on them? what was nokia thinking) handling terabits of throughput really puts things into perspective.
Anecdotally, the reliability has also gone up considerably, no more weird undocumented errors noone has ever seen or heard of before, where even replacement hardware had a good chance of not working. Compared to today, where even with thousands of nodes in the network, many days can go by without anything going wrong at all. And even if, more often than not, a reboot or throwing in a replacement piece of hardware will get whatever it is back up and running. And if something bigger goes wrong where you actually have to troubleshoot a complicated fault, you start to appreciate how it truly is a wonder all this stuff works at all.
Though I'm sure in a couple years I'll think back at how I thought a 400Gbit QSFP was sick, while handling whatever godforsaken thing the industry has come up with by then. I can't wait what the future brings us, even just in telecommmunications. Eventually we might get 100G links to residential customers. Or we might optimize everything so well we won't need higher bandwidths. Who really knows at this point.