If everyone gives up mining bitcoin will end up centralized.
That would be true,....IF mining wouldn't be centralized pretty much already.
Most of todays "miners" actually aren't miners, they're just hash-sellers, selling their ressources to a pool.
The only real miners are the operators of those pools.
How exactly is mining centralized now?
Compared to those days when there were no pools (and yes, i've been around at that time), mining really is
pretty much (you missed that) centralized now, done by only a handful, or maybe a couple of hundred pools.
Of course you can still switch to another pool if you don't like the decisions of one pool-operator, but first you have to actually know about those decisions.
However, it was way less centralized back in 2010, although there's way more "miners" today (rather call them "workers", that's more accurate).