'Cos they're not inconsistencies I imagine.
So if Burke and 'The Company' know of the xeno's existence (and the company have known since Alien right?), and all the billions of wealth that alien tech can bring, why is the mission manned by just a bunch of incompetent marines (not even SAS calibre)?
Simple - as addressed in the movie for those paying attention - 'The Company' didn't know. Burke was acting on his own because he didn't want to "make a major security situation out of it". If The Company knew they wouldn't have sat on their hands for 57 years - or even sent tug jockies in the first place.
Where are the scientists? Where are the biologists? Where are the company suits (other than Burke who is an idiot)? Etc. etc.
Again, all answered in the film. Burke was acting on his own in order to get exclusive rights in case Ripley was telling the truth.
The plan described in Aliens by Ripley is by no means a plan for a billion dollar company to aquire alien tech. What was Burke's plan before they landed?
He didn't have any plan. If the colonists really had found the ship, and if the Alien was as dangerous as Ripley suggested and if he could get his mitts on a specimen (hence his objection to nuknig the colony) - great. But prior to that he knew as much as everyone else.
None of this is explained in the movie... it's just forgotten/brushed over for the sake of convenience.
It's been explained in the movie, and it's been explained again here. If you choose to shut your eyes and go LALALALALALA! - fine. But don't make shit up to make a non-existant argument, and expect anyone with more than half a brain to buy it.