This is very true, at least in the eyes of some. It can be a very complicated issue

So what exactly do you want to solve about this type of terrorism? Should they be more selective in their targets like serial killers or should they kill larger groups of people? I don't think if you really stop and think about it the fact that they feel they can get their message out by killing less people is necessasarilly a bad thing. Sure it makes the barriers to entry into the feild lower but I suspect given the limited number of people interested in joining terrorist causes that the total body count is still reduced by that.
Now if we could simply direct terrorist organizations to fighting other terrorist organizations with whom they disagree, then we can convert the whole thing over to global scale gang violence.

Why do you think the US military is so big among right-wing whackjobs?

I believe terrorism to have three main reasons for existence:

a) It works for some political gain or it's perceived as such by some parties.

b) It's a completely asymmetric form of warfare, much like British General Rupert Smith wrote in his excellent book Utility of Force. Terrorism can't be fought in conventional warfare of state vs state in a battle of strategy, morale and industrial might. The new conflicts require smaller and smaller armies with light equipment and rapid deployment. This has been labelled war amongst the people, since everyone can be a combatant, unlike previous era where uniforms or plate mail would identify combatants from civilians.

c) It's much more doable by groups with small resources and requires little coordination, even less in case of suicide attacks.

If you plan to launch many suicide attacks you do need a larger group, but suicide seems to be a less and less popular option amongst terrorists. The fact that US forces have proven adept at killing suicide bombers before they can detonate themselves may be a signifigant part of that...

I highly doubt that. Suicide bombing is largely irrational and motivated by extreme religious or political views. I'd bet it's less common because as a whole terrorist groups that promote suicide bombing are less popular than, say, 2003. Plus the strategy of attacked States declaring suicide bomber's families as targets after detonation seems to work wonders.

My theory on the decrease of suicide bombers involves natural selection.

Sometimes they do it for the money.

+1