Market cap is, IMHO, not the best measure so. Revenue or market share seems a bit better. As an example, Japanese companies used to have huge market caps in the 90s, today not so much. Those companies still exist so, and are quite large players in their fields.

And to be honest, Google is more ad-tech then anything else, Netflix is entertainment. Amazon is, depending on how you measure it, 50% retail / logistics and 50% AWS. Which leaves MS and Apple as true tech companies, while Facebook is social media.

Retail, as in eCommerce, was ground breaking tech when Amazon started. Today, comparable tech is available from vendors like Shopify (web shops) and WiseTech (logistics and fulfillment). Social media was ground breaking when Facebook and MySpace came along, now it is more about selling ads then anything else. Streaming was ground breaking when YouTube and Netflix came around, now there are countless streaming services. And some of the older ones, looking at you Amazon, resembles traditional TV a lot. After all they sell ads now between streaming (FreeVee or what's it called) and broadcast new episodes on specific days, looking at you Amazon and Disney.