Trading Aaron Donald is asinine.
Is it? Why?
I can see reasons why it would not be wise by the Rams - he is a genuinely great player, a true difference maker.
Against that, we have a new HC trying to establish a change in culture, team over the individual - and the first thing AD does is hold out even though he is under contract for two years still. None of us have the exact details, but the rumors are that he has been offered a ginormous contract, and is holding out for more money AND an opt out (i.e. - if he is worth the ginormous contract, he gets to leave to go elsewhere - if he isn't worth it, the Rams will have given him a ton of guaranteed money). If this is the case, then keeping AD means that the Rams will lose multiple other good players.
What if the Rams get offered enough in trade that they feel it is worth it, especially if AD turns out to only want to sign if his contract is so large that it will make it difficult to build a good team everywhere else?
The Rams likely won't get offered enough to make it worthwhile to trade him - but if he insists on being paid a cap busting amount, and will hold out each season much of the year, so that he reports just in time to be absent or ineffective most of the time - it may make sense to trade him. Especially so other players don't figure they can hold out for more money too, despite being under contract.
Remember the Patriots - I hate them, but they build their team with depth everywhere on the field to keep them always competitive. Excepting Brady, expensive players end up going elsewhere as free agents or in a trade.