There seems to be a general assumption that Fabinho will be fit and available for pretty much every game throughout the remainder of the season. With Matip's fitness perennially unreliable, what happens if Fabinho also gets injured at any point in the coming months?
Liverpool really aren't that far away from a scenario whereby Phillips, Williams and Henderson are the only remaining CB options. And when there's a Premier League title and Champions League campaign at stake, that's a massive problem.
Completely get why signing the ideal kind of CB for the right price in January is difficult, but the risk of not signing anyone feels so enormous that it could define whether the season is ultimately a success or not. Surely worth compromising on a short/medium term solution.