There is another hope in this regard, when the mining will not reap much profit, all the big miners will leave the scene and then home mining will be possible if anyone is willing to support mining and as a reward you will get the mining fees.
Then Bitcoin will be a sitting duck for anyone who wants to launch an attack.
Dunno how mining will work itself out but it needs to be as muscular as possible if BTC takes a step up in use and visibility. There'll be an ever increasing number of entities with an incentive to mess with it.
If 20 million people all had a few asics maybe that wouldn't be an issue, but home miners will be way more fickle than larger and more committed operations.