Well, no doubt that the basics of playing bass, as long as you stick to just root notes and don't care too much about how it actually comes out sounding, definitely is easier than playing guitar.
I would claim that playing bass well or even mastering it is just as hard as any other instrument.
I kind of can relate to your story though.
I started out playing guitar, and was quite decent actually at it too, then I someday picked up a bass and the first infatuation for the instrument that was to become my main instrument of choice started.
A love story that quickly picked up pace when I shortly after decided to answer and add by a drummer and guitarist/singer looking for a bass player to join their pursuits in making melodic noise rock.
I went to an audition knowing very little about playing bass and I didn't even own one myself at that point.
After the audition I was sold, they complimented my bass play on how what I came up with for their songs fitted them perfectly and added to them further, actually the exact words from the drummer who was actually a quite skilled musician even back then, and both knew both how to read and write music and also quite adept playing on guitar and piano as well, was that he was impressed by my bass playing.
Somehow it just seemed to come more naturally to me than playing guitar.
Suddenly there was room for me using the small pieces of melody I always had in my head when playing songs without it sounding out of place, on the contrary they worked perfectly on bass lifting the songs further.
For the first time I actually felt 100% comfortable playing with other people, and felt like I could relax more.
Also I loved both the feel of playing the bass and the full deep sound of it much more than the guitar.
Yes, I felt that I was actually truly at home playing bass.
Soon I knew that bass would be what I would concentrate mostly on in the future, and guitar quickly became a second choice of instrument.
I still play guitar though and me playing bass has improved my guitar playing a huge deal as well.
I have evolved a whole lot musically since then, but still bass is and will most likely always be my main instrument and choice for expressing myself musically.
I'm better at pulling the strings from the back line, instead of being a flashy puppet up front I guess
I think the point is, that some instruments just speaks to some people more than other instruments, and naturally those will become more fun to play for said person and thereby also seem more easy, simply because you feel more relaxed and comfortable with them, right from the moment you pick them up.