During the 1870s, and again in the 1890s, the National League was the only game in town, and if you had major-league ball in your city then you were assured of seeing every team and every player at least once a year. During the 1880s the rival American Association was formed, and the two leagues didn't play each other; as a result, most ballparks only saw half of the total number of clubs, with the occasional exception of some parks that were shared, and the nascent pre-modern World Series contested during that decade. After the AA collapsed it was back to one league with the number of parks in use dwindling to eight by the end of the century.
Then the American League arrived in 1901, once again splitting the major-league teams into two circuits, a situation that persisted for another ninety-seven years. Again, with the exception of some stadiums like Sportsman's Park which were shared by clubs from both leagues, the only way a team could visit a park in the opposite league was via the World Series. The Yankees managed to face all eight NL teams in October by 1957, though by then some of the senior clubs had since changed parks and even cities. Then came the expansion era, and the rapid replacement of older parks, and it became impossible for any team to stay caught up.
Finally, interleague play was introduced in 1997, and AL clubs could visit NL parks during the regular season and vice versa. However, the concept was initially limited to corresponding division opponents and "natural rivals," and when different interleague divisions were finally phased in there was little concern given to keeping home-and-home matchups "even"...a team might host an interleague opponent several times in a row without ever returning the favor, and in the most extreme example the Padres didn't visit Toronto at all until 2016. And on top of that, ballparks continued to be replaced at a brisk clip, meaning that when a new stadium opened it had to "start over" with all potential visitors. Though we've gotten close to completing the grid in the last few years, the opening of Truist Park in 2017 and Globe Life in 2020 caused teams in both leagues to fall behind.
At long last, the schedule changed this season, accommodating for all teams to play all interleague teams once a year. There wasn't enough room to home-and-home, so you'd play away against half the teams and home against the other half, and then switch locations the following year. So we would be guaranteed to finally complete all ballpark-specific matchups within two seasons...provided they hold to the plan.
While I haven't yet confirmed that every team has held to the alternating plan, we have finally received next year's schedule and all of the "missing" park/visitor matchups, -- five going into 2024 -- are being completed. Truist Park will see the Guardians for the first time, and Globe Life Park will host the Cubs, Reds, and Mets in turn, until finally the Pirates arrive, and 30 existing teams will have played in 30 existing parks. The grid will be complete, and all will be right with the world...until the A's move to Vegas. But at least this time we'll only have to wait another two years.
Acuna going 40-40 and hitting at a .330 clip would also be a huge historical feat, but realistically, would it be enough to overcome an 80+ year old record being beaten (even if Arraez ends with single-digit homeruns)?
What records do you think will never be broken? Personally, I think 5 consecutive home runs in a inning will never happen.