Most people do take on hobbies, but not regularly. "Build your very own radio controlled Spitfire! With the first number, the wheels! Every Sunday in your paper shop!". I'm quite sure that 98% of the people who start it don't even get to the wings. Instead they have the antena of a U-boat, and the steering wheel of a classic Ford T. All of them 1:20. None of them will ever be built.
Then there's the pleasure issue. Ask some of those DIY-ers how pleasurable is to hear "oh, very creative bucket you've made" after weekends of hammering their own fingers trying to build a stool.
Most hobbies though cause G.A.S., especially among men. That is Gear Acquisition Syndrome. We spend more time and energy thinking and planning what else do we need (even though we do not need it) and then buying it than actually practising the hobby!
There are some which are especially dangerous. Photography for instance, getting into the DSLR world. You can always upgrade the camera body, or get a new lens, or a flash, or... the list of gadgets is immense. For me it isn't so bad yet... I have one camera body, three lenses, a grip for the camera and two tripods (which were gifts!).
People not musically trained but who take on some musical instrument are also dangerous. I've heard once "guitars? you just need one more. No matter how many you have". Then you go to amplifiers, pedals, software, ... the result is more time is spent reading about "the musical properties of the combination of alder and rosewood" than actually learning to play! Other than playing badly, this is the consequence:
Those two I know, because I suffer them. And it gets worse because I like to keep things in their proper place. More precisely three camera bags. I try to justify them saying that they have different purposes and sizes. Two are backpacks: the light one, and the big one (which can host a laptop); the third one is a shoulder bag. The guitars need also their own cases (two) and bags (two), plus two stands (an individual one and one that keeps 5 guitars) to keep them handy.
I'm told that there are other terrible hobbies: golf, aeromodelling, video recording and production, hi-fi systems and I have witnessed acute cases of knitting as well!
How about then redefining hobby: an activity done seldom, for which gear is investigated and bought regularly in one's leisure time, for no discernible reason.
Not sure if writing is a hobby, but I shall now stop and go and take few pictures and play some guitar before the next G.A.S. attack hits me!
PS: a hobby that I can recommend since other people enjoy it is cooking! It's fun and others get to enjoy it!