How do you define a Tech giant?
By Market cap they are #1. Here are top 5.
1. Microsoft $895B 2. Apple $888B 3. Amazon $867B 4. Google $816B 5. Facebook $473B
They have been in top 3 for last 30 years with a robust business model. They missed on Mobile and search but hey it would be hard for any tech company to top in each market.