Why not just off Clay? (Possible spoilers)

I'm up to S5 on Neflix. For those who watched the series, I have a general question.

Jax has now assumed command of the MC and is working on some convoluted plan to isolate Clay, expose him as a traitor trying to usurp Jax and then take a club vote on whether to oust Clay from the club in a 'permanent' way.

Why bother with all this? We know that Clay simply killed Jax's father via a faked accident. Nobody questioned it. Why doesn't Jax just use the same play? Clay has severe arthritis / rheumatism... the obvious thing would be to
stage a crash, then blame it on Clay losing control of the bike.

Separately, it stretches believability the way various characters are able to "deduce" the long plays at work. Jax is able to deduce Juice is the mole just by a pretty big stretch of deductive reasoning. Clay is able to figure out Jax is co-operating with the feds in much the same way. These bikers seems to have better abilities to work things out in their heads than cops.

It sometimes seems that the writers couldn't figure out how to string together events that tie things together. Instead they just decided: "Okay, this character simply figures things out in his head based on a combination of good guesswork and intuition. We'll have a exposition scene where he just announces his firm conclusion with no actual evidence to support it."