Not every team needs to be improved from the outside; some just need time to develop, play together, and be healthy. Also Salah, Solanke and Robertson have all looked very good in pre-season and were signed this window. What has Chelsea/Arsenal/Tottenham done that's so much better than those signings?
They may or may not lose Coutinho, and the window is still open. Most places believe Liverpool should still get van Dijk, and it's very likely they'll buy a replacement for Coutinho should he go. I'm confident because I believe in the team, the manager, and the players from what they've shown last season and into this pre-season. They weren't a team that needed to add a lot to step up a level. A defender, a forward and maybe a midfielder. Coutinho moving back provided the midfielder, Salah/Solanke were forward additions and we added Robertson (though they still need a CB, which is what I said before).