When these celeb suicides are reported, you don't know just how messy and/or painful those suicides were. News reports are usually vague on such things, sometimes not even reporting the method. You sometimes read "no suspicious circumstances" or "no futher investigations" and assume it's suicide.
People on this forum are generally eager to avoid pain and mess (in a sense, that's WHY we're here) and consequently we may spend more time researching methods. I won't say it's easy to reach for a gun and blow your brains out but if you have a gun and you're doped/boozed up then it might be more of an impulse thing than anything considered. A news report generally won't indicate things like that - you just read of the end result 'x is dead'.
Access to resources is a big factor I'd guess, and money facilitates easier access. But also consider people with access to, for instance, pharmaceutical grade drugs (people like doctors, vets, paramedics, nurses, etc etc) - I'd guess they number highly in the list of suicides... just because it's 'easier' for them to get the stuff to do it. Perhaps ditto for people with acess to guns (police, military, etc)...
People like me (and maybe you), we can't lay our hands on the resources readily. We don't have the direct access to them, or know someone - or can pay someone - that does. So we have to read up, find the methods which both work and feasible for us.