I think the comparison to 2001 is there, it's just shallow. If I gave a general description of the plot to 2001 and Interstellar, they'd come off as very similar (though I haven't seen 2001 in over 10 years so maybe my memory is off).
Basically, mankind discovers an anomaly in space. A mission is sent out to investigate this anomaly. Things go awry in the mission, a member of the crew sabotages the mission which forces the main protagonist to an action that is very dangerous. The protagonist ends up in a room where trippy shit happens that will make a lot of the audience go 'huh?'.
Now to me, that sounds like both movies, but it's all in the how and why things happen that differentiate the two films.