I find it interesting that despite losing so many staff members since 2018, OLM has been taking on more projects since then, Komi, Odd Taxi and Summertime Render. And a lot of the more known staff worked on Evolutions. Seems to me like OLM might be trying to focus on newer projects since the above anime all released pretty much back to back. I'm guessing they're not really prioritizing some of their staff working on Pokémon as much. I don't think anybody can deny staff shortage as a contributing factor as well but there's still massive signs that the issues have primarily been from within.
Taking on more projects is something most studios inside of the industry do. Producers are not good at managing studios, which is why so many tend to fall a part. In this case, OLM's executives are likely taking on projects because they need to bring in the money to keep the studio going or because they're just mismanaging their resources and doing what their partners (other members of the production committee, who have the rights to make an anime) want them do.
In the Japanese animation industry the people who make the project (directors, writers, animators, production assistants, sound design team, coloring team, filming team, backgrounds team, etc.) DO NOT decide what projects the studio takes on. A studio like OLM—which is the main production studio for a series rather than just a sub-contractor working for another studio—is not usually run by an animator or director.
The Pokemon production team has likely suffered over some really major losses over the past seven or eight years. In 2016 Studio Cockpit (which had worked on the series since the 1997 series' Episode #3) closed. The studio that brought us Tamagawa, Iwane, Asada, Natsume, and Koga was no more. Iwane and Asada opened their own two-man studio to continue working together on Pokemon, which they named Studio Cockpit (written in Hiragana, as opposed to the original having its name written in Katakana). Everyone else from the studio left to join other projects. Cockpit was a pretty important sub-contracting studio that had a history of working all over the industry. They closed down because the president (Masunaga Keisuke, I believe?) decided to retire and nobody else within the studio wanted to take over running the studio. Now, Pokemon no longer had the services of Studio Cockpit to work with, a studio with a rich history of Kanada School animators.
In 2018 sub-contractor Studio Wanpack also closed down, which hurt the entire industry in general. Wanpack was a big studio that mostly handled the bulk work of the industry. It was never a healthy studio but it still essentially helped carry the industry for years, during harsh times. With the studio gone its staff either left the industry, went freelance or joined other studios (if any studio was hiring in-house staff, which is always more expensive than just using sub-contracting studios or freelancers).
So, the question you're probably asking is: what exactly is the advantage of a studio? A studio makes organizing staff easier. Right now, a big part of why the industry is in such dire straights is that production assistants (overworked, under-paid gophers) will often have to travel in-person around the country to collect an animator's work and bring it back to the studio for final approval. OLM did streamline the process a little bit during Sun & Moon by investing in digital tools (animation software, which makes simply sending a digital drawing to the main studio instantaneous), but not every animator does that. Furthermore, in terms of the industry, the industry is still mostly analogue. Animator supervisors (the people who correct animation drawings to make them look more on model or just plain cooler or cuter) wind up sitting around with nothing to do for a lot of time because they're waiting to get drawings, either because of the slow transfer of an animator's work to their location or because of nobody having been assigned those shots. This is where the large number of animation supervisors now come into play. Episodes on recent Pokemon episodes have risen from 1-2 per episode in large part because animation supervisors (people like Yamazaki Rei, for example) are receiving the key animation drawings very close to the broadcast date. Normally you'd give your animation supervisor a month to actually check an episode's key animation drawings but now they don't have that time, so they need to split the work with other animation supervisors.
So, remember I mentioned Studio Cockpit (the original one)? Let's go back and at the credits for Episode #3:
Storyboard & Episode Director: Asada Yuuji
Animation Supervisor: Tamagawa Akihiro
Key Animation:
The cool thing about this episode? Everyone working on it (the in-between animators, too) work at Studio Cockpit. They were all in the building together (well, most likely) during the production of the episode's animation. This means that everyone can actually communicate with one another to know what is needed for the episode. Many modern cartoons simply no longer have this luxury. Episodes are a mix of people working from home, OLM, sub-contracting studios or even a sub-contractor somewhere overseas, like TAP (Toei Animation Philipines).
Whoops, accidentally went nuts with this one.