Let me put it a little less bluntly, cos it seems the message is not getting through.
Lucas is not the reason we are only scoring a goal each game. Lucas is not the reason we concede a goal each game. Perhaps Lucas is the reason we are not conceding more goals each game, but if that is the case then surely we should be a lot more worried about our defensive line than the absence of a midfielder?
Point remains: losing Lucas will be problematic because we do not have the same quality of cover. However, it's a team game, and if the players nearby that position can raise their game (eg the way Adam generally has this season thus far), and if our front line stops firing blanks, then effects of the loss of one player can largely be limited.
Ergo: since we can't improve our defense, maybe, just maybe. it time we turned up the heat in attack. Consider Man City, who have a dismal defensive record in every competition, yet they're 5 points clear at the top of the league (undefeated, only 2 draws), are in the league cup semi-final, and still have a chance in the CL group stage. It's time for the expensive buys to stand up and be counted.
LFC > Lucas.