It was intended to bring the existing Julian calendar in Eastern orthodox churches closer in to line with the gregorian calendar. It was not meant to be a universal calendar.
It's not realistic to alter the existing calendar in this day and age. The gregorian calendar was already too embedded in 1923 to change, and now it's globally dominant.
The only way to replace the calendar now would probably have to be a brand new calendar (to prevent confusion with the existing calendar, it'd need new month names for example) OR a global agreed change to the gregorian calendar.
Neither is likely; there doesn't seem to be a big enough need or benefit to get countries together to change this. They can't even agree on action on pressing crises like the climate crisis.
Guessing not much will happen to the calendar until (well, if) mankind ever settles on other planets. Some universal mode of timekeeping would need to be decided upon for consistency between planets with differing day and year lengths.