Spam can be difficult to stop on IRC compared to modern webchat applications. From lacking things like javascript, captchas, cdns, and so on, to having a distributed network architecture and fewer ways to verify users.
You have exactly as many ways to verify users as are implemented in your NickServ, and pretty much every snazzy web-y proprietary chat platform has a "distributed network architecture" as well.
IRC has plenty of real problems, but your particular list of arguments seems completely irrelevant.
Sure, people have written bots/services that have become part of some server packages' standing offering (chanserv, nickserv, opserv, etc.) but there's no spec for them, every server's implemention has (sometimes wildly) different command sets, and as effectively text-scroll CLI, they don't actually make things all that much easier. They're a chore to use. And I say that as an IRCop.
IRC as a platform is insufficient in today's world, so if you're going to spend a lot of time either finding -- or more likely, making -- services to take care of all the administrative tasks that IRC itself does not cover, you might as well just go one step further and go "you know what? IRC isn't sacred, if we're spending time and money on trying to make it usable in 2019, then how we instead spend that same time and money on finding a good solution to the problem we're having, rather than sticking with IRC for no good reason".
In what way are any of these technologies relevant for a chat platform?