I am more familiar than most with how the MVC has handled this historically. That's because most of the posters here are fans of schools that the MVC added after losing one of their top teams.
I doubt this is the exact way any specific replacement went, but the MVC essentially replaced Louisville with Evansville. Replaced Memphis with Indiana State. At the time many of the current members were added, they had been the equivalent of UMKC or Southeast Missouri in the current situation.
Look for the Valley to immediately take action and add a school that irritates every fan of every Valley school. That's been the historic pattern for the last 40+ years. That school will become better because of their membership in the Valley, but they will dilute the conference and the SoS and NCAA at-large possibilities of every current member. That's the MVC way of doing business.
There are many fans here that are really irritated by WSU's fans criticism of the Valley for inviting their school to join the league. Wait till it happens to you. Wear that shoe and see how it feels. Then you might better understand the irritation that WSU fans feel for what the Valley has done when one of the top-tier team leaves.