E3 was necessary in the early days of gaming but over time lots of big players in the gaming industry began to pull back on public events even before the pandemic hit the world and that was already a big loss for E3. The transformation of a business is always the roughest and many don't survive. E3 just couldn't keep up with interactive virtual events and the new ways of hosting an event.
Thanks for the run down on the life of E3! Hopefully more gaming conventions pop up and allow players the opportunity to physically participate with the companies and developers.
I think it's a goodbye to E3, although I think something similar to this idea will appear in the future.