Greg just keeps brininging it up because so many people took it seriously at the time even though that was clearly not going to happen unless Oda really hunkered down and rushed a bit.
And for a little while, t seemed like he might be. Oden's flashback started setting up and covering a lot of material that would otherwise need to be a flashback for Roger/Laugh Tale later, and he started speedrunning and offscreening stuff like the samurai facing Kanjuro, and then taking them all out in a single chapter against Kaidou.
But... that Oden flashback was the longest in the series. And after Oda got past the rush to chapter 1000, he backpeddled and redid all the things he sped through, and it just took another two years to get through the Kaidou fight... he can't help himself.
He was really determined to legit go for it for a couple months I think... and then didn't enjoy the results he was getting from rushing. Even when Oda said it 4 years ago I said there was no way he was doing it in less than 8.
So then he bought himself another year when he answered the SBS question a year later and stated "five years" at that point.
And more recently he realized there were people taking him at his word and worried he was rushing, so he had to reassure us "it'll take as long as it takes. But final arc, honest!"
I estimated ~1200 chapters for about a decade, but Cakeland and Wano both went so long I switched my estimate to 1300 mid 2021 when we had a better idea of the Wano timetable.
30th anniversary still seems about right, but that's going to be entirely dependant on if he can do Elbaf in a year/40 chapters, If he does then it's feasible he wraps in 2027. If Elbaf is another mega arc though, there's just no guessing and it'll be as long as it will be.
Also, do you count the 30th anniversary as January 2027, July 2027 since the series started in July, or June 2028 because that's a year? That's 40-60 chapters of wiggle room depending how you count.
July of 2027 would put him at about 1,260 chapters, June of 2028 would be closer to 1300.