Everyone having a copy of the whole blockchain is not needed. What you need is sufficiently distributed hashpower that no actor can perform a 51% attack. That's all.
Small-time users can use thin wallets; mega-power users can download the whole blockchain and spend whatever (in perspective, not super significant) amount of money they need for sufficient storage. Users in between can carry a reduced form of the blockchain that doesn't care so much about a full transaction log but accurately describes the state of every wallet's balance (thereby functioning the same from a "verify that they're not bullshitting me" perspective).
You just described a way to decrease the security of Bitcoin. Users already decided collectively that no amount of security should be exchanged for other features inside Bitcoin. Even taproot, which is a relatively small change takes years to get to a point that it's accepted.
It's like Kosher food: if a small percentage of people want food to be kosher, it's often easer to make all food Kosher.
As Michael Saylor says, Bitcoin is good enough to store hundreds of trillions of dollars. Just don't f*ck it up.
Small-time users can use thin wallets; mega-power users can download the whole blockchain and spend whatever (in perspective, not super significant) amount of money they need for sufficient storage. Users in between can carry a reduced form of the blockchain that doesn't care so much about a full transaction log but accurately describes the state of every wallet's balance (thereby functioning the same from a "verify that they're not bullshitting me" perspective).