Sync committees were introduced in Altair.
The following three upgrades would likely happen sequentially, each relying upon the other to
set the necessary groundwork. With each new iteration, Ethereum would greatly broaden it's ability to allow participants to interact with the network.
I.e., make it easier for lightweight devices to independently verify the state of Etheruem. Today, most users outsource this responsibility to third party RPC providers.
Beyond accessibility, SNARKs and STARKs have the potential bring privacy to end users while still allowing for some amount of transparency
where needed. There are also security improvement achieved by both, particularly in regards to quantum resistance.