Is it muttar for one to get drunk on Purim if this will cause him to miss davening maariv with a minyan (due to his drunken state) even though he will still daven maariv on his own?
It is permitted to get drunk even if this will cause a person to miss Maariv with a minyan.
However, this should be avoided where possible.
See here where we discussed at length the different opinions concerning drinking on Purim.
If one’s custom is to get fully drunk, one does not have to take davening with a minyan into account, since according to many authorities this is not a full obligation but rather a hiddur. Also, one gets drunk before the time for Maariv comes, so that the obligation is not incumbent when one gets drunk.
See also here for a similar answer in Hebrew.