Follows from discussion in #48052

We noticed this while performing load test on 4000 node clusters with services enabled. The iptables restore step in the proxier fails with:

E0625 09:03:14.873338       5 proxier.go:1574] Failed to execute iptables-restore: failed to acquire old iptables lock: timed out waiting for the condition

And the reason quite likely is because of "huge" size of iptables (tens of MBs) as we run 30 pods per node and each pod is part of exactly one service
=> 30 * 4000 = 120k service endpoints (and these updates happen on all 4000 nodes)

cc @kubernetes/sig-network-misc @kubernetes/sig-scalability-misc @danwinship @wojtek-t