It wouldn't be difficult to include a little "" icon on each post that, when hovered, shows probable location or the creation origin. It's true that VPN's will often muddy this info, and even things like phone number confirmation for 2FA or billing address for Verified badges can't be 100% reliable... but it shouldn't be too difficult to say in those cases "User likely masking location" if the pattern is detected.
It's not about being easy it is about being profitable. I don't care where you fall politically, accounts like this increase engagement and thus profit. Companies like profit so this type of thing despite being much easier than some might assert is going to be slow to do. You can have legal requirements around identification for accounts over 2K followers. It basically would never inconvience people unless they are trying to be an influencer
The largest effect is that X suddenly (out of nowhere?) started to mention this, publicly. Which, given mr. Musk's political stance (who himself has been the target of a campaign, likely from mr. Putin), wasn't intended to have this effect.
If you were to share this information publicly from the start, the troll/propagandist/agent would know this information is being shared as-is from the start, and they could adapt. Very likely they would adapt. Therefore, the effect would be much less severe.
It is also very obviously PII, which would hurt innocent people (likely a minority but I can imagine it happening).
My take: intelligence agencies were already interested in said information and mr. Musk was like "whatever, we'll just share this with everyone".
russians been interfering with other countries through all possible channels for decades.
They integrated with every single Ukrainian election (including the most recent one in 2019), they tried hijacking (with various success) elections in Romania, Moldova, Lithuania, Czech Republic, Estonia, etc..
This includes radio, tv, printed periodics, social networks, even popular music, movies, tv series and books...
So how much are you willing to bet that this time it's definitely not russians?