On a team of 13+, coordinating remote day per week plus late starts for kid-drop-offs / early leaves for kid-pick-ups, vacation days, etc. makes it very hard to figure out when you can actually get the team together. In practice, the members of the team also suffer because you can't plan when you're going to block on needing to talk at a whiteboard with someone. I've also found colocation to be the only way to handle complicated design tasks.

Team members who are around tend to exclude people who work remotely during key hours, relegating them to the easily separable work, which results in less impact and ultimately less pay and promotions.