Can you provide some rationale for this part of your post? I categorically disagree with both aspects of this statement but am happy to be enlightened or even corrected, and even if I'm not convinced I always enjoy your perspective.
Second point first:
Liam is in no way necessary to any story at this point except the good wife path which I personally believe is the favorite of a very very slim percent of players. If eliminated Morello would simply transfer the gambling debt obligation to Sophia. Where else is he even important, let alone absolutely necessary?
First point second:
No one thinks Liam should bed down with the fishes. I think everyone thinks Liam should bed down with Cathy, an opportunity made available because Sophia stayed at Sam's concert, get discovered by Andy who tells Sophia who tells Alyssa who tells Carl who takes out a contract with Morello to whack Liam that get's taken up by the hobos who completely botch the job having become insecure in their toughness and resolve having watched Dylan pummel one of them, which results in Liam getting badly injured and limping off to the other side of the park near the statue where he collapses and gets shit upon seven times by seven different pigeons before he's discovered by Alyssa who is walking to the nearby coffee shop to deliver a Antonio's ignition key to Sophia. The key just happens to be blue.
Well, the first & prime reason for Liam's continued prescence is the fact that it's his job keeping a roof over the Parker's heads. Sophia could never afford that palace on a teacher's salary, even if she doubled the number of side jobs. That makes him necessary for every branch of the story. He works very hard, even to the extent of receiving a fax, (an unforgiveable faux pas), while in the middle of some good role-play sex. OK, it's possible he may have gambled when he was supposed to be working but we don't know this, it's just speculation, mine included.
He's a faithful husband, an attribute which should never be underestimated, especially given the environment in which he makes a living. His prescence is conducive to the stable background from which Sophia can have her adventures, in the way she does. If that background were to crumble the story would take a different turn or two. I'm not sure how some of the storylines could be impacted. Perhaps we'll get to find out. He's been overcome by addiction sufficient to place it all under threat but for now it's all still there. We've been told he's not having an affair (up to now), by the Dev himself. As for looking at Cathy, my guess is we'd all have done that, even if just briefly, whilst feeling guilty.
Liam acts as a pivotal point. If he left or didn't exist, nor would any extra-marital sex event, if we ever get to see it!
Essential also is Liam's lacklustre performance in the bedroom, without which Sophia would have no need to think about the sexual potential of the situations in which she finds herself, (even though we've probably all done this, whether or not we had a satisfying sex life at the time) & thus a whole big excuse for corruption would vanish.
He's proven so unpopular, (& I'm not a big fan either, especially given his ignorance in failing to attempt to understand his own son's chosen sport but this is believable in context), that you need only refer to previous posts in this thread to catch a continuous theme of Liam detracting. This is despite the fact that like the villainous blackmailers, the cuckcolded husband, (or wife), is a stock character in corruption games. They are never popular with fans, often being made that way on purpose but are a vital reflection of an MC's corruption. As they become more ragged, weaker, stupider or downright deranged, so the MC's developments can be taken up a notch or two. There have been various suggestions for his departure, or indeed demise, or wait......, was that Aiden, or Bennett, or was it Dylan?