I think you have got it slightly wrong. You're correct that you can't just go to one community on one instance and see every new technology discussion that is taking place on Lemmy, but you CAN subscribe to all of the technology-related communities on different instances and scrolling through posts of communities you're subscribed to will show you all the discussions you want to see.
I think your concern is a common one, but what you're seeing as a bug is, I think, one of the best features of federation.
Drop the mindset that r/technology was the reason all of those tech-interested humans got together in the first place. It wasn't. The human community of tech-interested people just all joined the subreddit. If that same human community subscribes to all of the different tech communities on different instances, then they'll all still be interacting together online, all commenting on the same tech posts. No fragmentation.
The extra cool part is how stable this is. Imagine a mod of r/technology went on a power trip? Now the whole sub is gone. Imagine the mod of technology.beehaw went crazy? Not a big deal. Everyome unsubscribes from that community and the discussion carries on in the different tech communities. Or what if beehaw goes down for an hour? (Or forever?) Also not a big deal (unless your account is on beehsw!) because the rest of the instances will still be up.
I expect we will see a feature soon(ish) to set up a multireddit-equivalent so you can just pull up the tech communities you're subbed to.