If Monero grows and there are 300k daily tx and a spammer comes in with 300k daily tx (as they have done already) Monero will come to a halt. If they can keep it up for a month or 2 Monero is done.

Bitcoin cash has had 500k tx spikes and no one even noticed. BCH has been tested up to 10 million tx per day. All the privacy in the world is useless if you cannot transact. Thus scalability is more important than privacy.

BCH needs more users so TX volume can sustain the chain, Monero needs to fix the scaling flaw which appears to be fundamental to the underlying protocol. I am betting on BCH 😉

The quantum threat will be solved years before it is ever an issue. BCH will flip to whatever algo it needs to survive. There will be a transition period of years anyway where both algo's will be used. This is a non-issue.

Looks to me like you are trying to divert attention from the fact that BCH will replace Monero as a privacy coin so you are throwing everything + the kitchen sink into the argument.