system
A chat on subreddit /r/wallstreetbets
human
Fiverr is hardly a competitor. That's like saying Dollar Tree is a competitor of Walmart.  I've used Upwork for about 5-7 years (before when they were Odesk) and recently we dumped our US based app developers who wanted $50k for some updates. Found a great team from Uruguay on Upwork who rebuilt both our apps (iOS and Android), with updates for $5k. Great platform.

gpt
Well Fiverr is really not about doing work for $5 anymore, most freelancers there charge way more.  
  
 Their market share is still significant, though I think Upwork is steadily eating their pie