The capital cost of the helicopter is so much higher than the capital cost of an aeroplane.
Well ... maybe not for relatively comparable acft:
New C172SP about $305,000 (U.S.)
New R44 about $425,000
Yes, more for the helicopter, but not "so much higher."
Also, the cruise speed in a 4/6 seat helicopter is (typically) MUCH slower than a 4 or 6 seater aeroplane,
Well ... maybe not for relatively comparable aircraft:
C172SP about 126 kts
R44 about 117 kts