Not even close. The Mellotron is the tape-based "protosampler" that defined a lot of music from the mid-1960s up thru the end of the 1970s or thereabouts. For example, the opening of "Strawberry Fields Forever"...those are the flute tracks from a Mk III. Great instrument, maddening maintenance requirements.
Now, Mutron was a spin off from ARP and they put out effects pedals that are VERY sought-out to this day. The Biphase was this amazing phase shifter that employed both swept and fixed/tunable filters and some really interesting modulation methods, and the original developer collaborated with Electro-Harmonix when they designed the Flanger Hoax. Flanger Hoaxes are a bit spendy, but NOTHING compared to the price of vintage Mutron gear!