The World Government is fucking stupid
Look at Luffy:
- Enters Big Mom's domain, fucks up her party, defeats Katakuri and leaves
 
- Enters Wano, fucks up Kaido's crew and base, defeats Kaido
 
- Has Awakened the Nika Devil Fruit, something the WG fears enough that they've spent centuries looking for it
 
- Has Zoro and Sanji, some of the best fighters in the New World right now, in his crew
 
- Has Nico Robin in his crew, the only one who can read Poneglyphs
 
- Has Franky in in his crew, the only Shipwright who had Pluto's blueprints
 
- Has Jinbei in his crew, once a Warlord and considered the most powerful Fishman
 
- Has Alabasta, Drum Island, Fishman Island, Dressrosa and now Wano in debt to him
 
- Is walking around with Shank's and Roger's Straw Hat
 
And they think he should have a lower bounty than Kaido and Big Mom who have done fucking nothing in these last few decades?