It's actually easy to take out Alshabaab for good but because until recently they lacked the capability. But with more military capability you can do a bottom up approach to tackle them and not top-down approach by drone striking the top leaders of the group, . They are easily replaced and nothing changes if structures that sustain them remain.
This was explained to me when i spoke to a Somali war veteran that my dad introduced me to while we were at a gathering.
All you have to do is target key areas. Then take control of key revenue streams like the ones i mentioned in another thread , how they tax the Gold trade, arms trade, charcoal, sugar, agriculture, transit, mobile money transfers etc
Alshabaab currently collects half as much revenue as the Somali government .Their routes/roads to move goods and products. Facilities where they house things. Confiscate vehicles and do checkings. We have all the information avaliable to us
Inside al-Shabaab’s revenue-collection machine
After that you air strike and take control of their training camps and grounds to knock off their manpower. I mean if journalists can just easily visit their training grounds .
Exclusive: Inside an al-Shabaab training camp How hard is it? come on are you kidding me?
It can be done in less than 1 month. All you will need is just a handful of troops and some air precision capability. You can start in the Northern Regions and then work your way down, by the time you reach their South central holdings and streams they are significantly economically impoverished then they will start to topple.