I was curious as to why liverpool are so skint this season. Then found this video. Don't know to what extent it is true, but I trust it.
Mainly says that the owner John Henry invested around 100 million US dollars when he purchased it. He doesn't extract money from the club, but rather spends it on rebuilding and renovating Anfield.
Also, they have a very high wage bill (among top 3 in the EPL, next to Man City) - and their recent buys - VVD, Allison, Keita, Mane, Salah has finally caught them up on transfer payments and wage bill; while at the same time the PL prize money is not more than 30-40 million pounds from finishing 2nd or 3rd in the table. Even then, their owners(FSG) have been very good at managing the club I'd say.
In short, it truly seems that they cannot purchase (Thiago) without selling one of their star players first.