The Crisis on Infinite Earths crossover was a major pinnacle in Arrowverse crossover history, but one that may not have held up over time. It was the culmination of years of work building to a crossover of this magnitude which featured multiple characters from all the franchise's shows, such as Supergirl, Flash, Arrow, Legends of Tomorrow, Batwoman, and Black Lightning. The endeavor promised two things; first, to pay homage to the iconic Crisis on Infinite Earths graphic novel story, and the second was the promise that by combining the worlds of Arrowverse shows onto one Earth, future teased crossovers could grow in scale, due to being easier to facilitate. Crisis succeeded in the first on a major way with a big-screen worthy event. As for the second, real-world circumstances have led to the failure of the Arrowverse keeping its promise of bigger and grander crossovers.
The Arrowverse crossover era began when The Flash’s Barry Allen paid visits to both Arrow and Supergirl. Each successive crossover grew in grandeur and storytelling, bringing iconic DC stories to life. The "Invasion" crossover could be considered as Supergirl's official welcome to the Arrowverse. Subsequent crossovers such as "Elseworlds" and "Crisis on Earth X", involved more ancillary characters from all the shows while telling broad, engaging stories.
Crisis on Infinite Earths crossover teased even grander Arrowverse crossovers. The final moments of Crisis set up what many believed to be the CW version of the iconic Justice League, featuring Supergirl, Superman, Batwoman, Flash, White Canary, Black Lightning, and Martian Manhunter. Smaller but equally impactful crossovers between Supergirl and Batwoman, and Black Lightning and Flash were also teased. All those plans have had to be altered due to the announcements of Ruby Rose leaving Batwoman, and both Supergirl and Black Lightning announcing final seasons, resulting in the loss of four members of the planned Justice League. Furthermore, the COVID-19 pandemic majorly affected how all Arrowverse shows are filmed, making crossovers financial and health risks. Even an announced crossover between Batwoman, with a new leading lady, and Superman & Lois was later scrapped, likely due to COVID protocols - effectively neutering the collaborative aspect of the franchise the Crisis had so painstakingly developed.
The Arrowverse post-Crisis has had to take a step back and regroup, rethink how to best approach the multi-show events that fans look forward to. Currently, Superman & Lois isn't even acknowledging the other shows or the Arrowverse, although The Flash name-dropped Superman in its recent return. Batwoman’s acknowledgment of the Arrowverse so far consists of one Supergirl mention in its season 2 premiere.
In the long run, having to break their promise of more crossover integration may benefit Arrowverse shows. No massive crossovers mean no schedule juggling and production delays in the show’s individual seasons. Planning large-scale crossovers have been reported to be logistical nightmares. Without the crossovers, Arrowverse shows don’t spend space and time setting up crossovers; this limited focus allows them to become more self-contained, making for tighter storytelling.
While scaling back the big crossover events may be disappointing in the short term, that does not mean the Arrowverse is abandoning the crossover concept. They have taken a new approach to keep Arrowverse shows connected, that being of the single character crossover. Although nothing has been announced by producers it would be hard to imagine Supergirl coming to an end without at least one more adventure with her superhero BFF, Barry Allen. The Flash's Jay Garrick just completed filming a Stargirl crossover and there are rumors of a Flash/Black Lightning crossover. And over course Arrowverse fans are eagerly awaiting the return of Arrow’s John Diggle who will visit multiple shows this year, fueling speculation that he may be laying the foundation for a CW Green Lantern. Even without crossovers, the Arrowverse is bigger than ever.