Re: US ban is little to do with security
"Huawei is killing Cisco's business in every country that can't afford, say, Arista."
Huawei aren't killing Cisco's enterprise business - cloud is. And when Microsoft realise that they need to develop their own networking kit to keep up with AWS/Google/Tencent/Alibaba, Arista's steller growth and ~25% of their annual revenue disappears.
Huawei are indirectly killing Cisco's voice/telco business because of the global move away from fixed line services to mobile, but that's been happening for years and Cisco haven't demonstrated a clear direction on how they will address this yet and why there have been rumours of a merger/takeover/something with Ericsson.
Your comments about Huawei apply equally well to many traditional storage/server/networking vendors that are being undercut by Huawei and other Chinese companies in their traditional markets and are losing existing customers to cloud providers at the same time.
Banning Huawei isn't going to slow the move away from traditional fixed line telco's - at best it gives you 1-2 years before Ericsson/Nokia catch up and deploy non-Chinese 5G networks.
Plus the trade war with China appears to have cost Cisco ~8% revenue. If Cisco wanted this, it was remarkably short sighted....they didn't even manage a brief bump in revenues for such a large loss and its unlikely they will see much of it return if the trade war ends.