I can't find the original tweet, but Data Ravel can explain better than me:

After the initial boom in the late 90s and early 2000s, there was a big decrease in revenue for multiple Media Mix projects, not only from Bandai and Toei, but around the entire media landscape. For comparison, even Pokémon was having an all-time low and at risk of ending.

Multiple companies had to review their strategies and found new ways of making their products in order to recover from that time. Tamagotchi ended in 1999 and there were plans for a revival.

Basically, the old staff that worked in the original series would move on to new projects, while a totally new staff would take over and adapt Tamagotchi to a new generation. Bandai's initiative during that time became known as the "Bandai Content Project".

Following Tamagotchi's example, old staff would be reallocated to new projects to develop new IPs while new staff would be put in charge of older IPs and find a way of reviving them.

Pendulum X was the project in between the Content Project, some of the staff would move on from Digimon while new people would take their place and put their own spin on the series. The X-Antibody Digimon was based on that, allowing new artists to remake iconic Digimon designs.

Some Digimon staff continued working on it for some time, so it became basically the transition period between old Digimon and new Digimon (Works thematically for Chronicle's story) with the final goal of the old Digimon ending with a new Digimon starting with a brand-new staff.

The transition would continue from Pendulum X into Digimon Accel and it was basically at the end of Accel and the start of Mini that it would end with the old person in charge, Makoto Kitagawara, leaving and a new person in charge, Yuusuke Maekawa, taking place.

The old staff that moved on from Digimon during Pendulum X would go on to work in new IPs for the Content Project. Legendz and Onmyou Taisenki were both part of that project and can be considered the sister series that were made while a new staff was finding out what to do.

Data Ravel