Musk got rid of the people who owned the relationships with the brands and agencies that drove the ad revenue. Burning those relationships plus getting rid of content moderators made sure advertisers were very skeptical of being on the platform. Then there's the GARM lawsuit causing that tiny org to shut down, suing another non-profit for point out brand safety issues, etc.
I thought the advertisers pulling out was more a direct result of the tweets he posted or liked. Perhaps those relationships were strained already due to what you've pointed out, but I don't know that those employees could have made a difference in relation to those posts.
It was Musk's actions.