The hard truth is that the Mississippi schools are very lucky to have been original members of the SEC. Neither of them would be on the invite list if it were being reworked today. I also think it's not guaranteed that the current SEC makeup is static over the next 5-7 years with the shifting landscape.
UM is doing everything it can to justify its continued membership in the SEC; they're laser focused on it as an existential strategy. Plenty of people hate Lane, and he is a ridiculous person, but he is mastering the PR aspect of SEC relevance, which is having people talk about that program. And the administration (athletic and academic) is clearly behind this strategy for the existence of the school.
If State is actually "pivoting" to baseball more exclusively, this is probably the strongest way to strengthen its brand to stay SEC relevant. I realize that's not a perfect comparison since baseball isn't a revenue generator necessarily, but I would liken it to being a basketball school 25 years ago.
ETA- they're not on the invite list because of the relatively tiny media footprint that the schools have. Just not enough alumni or eyeballs for media.