Skirting a discussion on how relatively good or bad Netgear are, the results seem to be vague as to whether they're resolved, how bad each vulnerability is, and it seems to list a device for each firmware version. I don't think the front-page numbers are necessarily particularly helpful.

You're right that the bulk of them will have been resolved... but... given the sheer continuous volume of them for Netgear, does that actually help?

It seems there will always be enough undiscovered or unresolved vulns "in flight" to compromise it on demand.

If the router allows 3rd-party firmware and well-maintained ROMs are available, why avoid the hardware (unless you don't want to apply the upgrades)?

Cable modems typically do not allow this; only the cable provider is able to apply oem firmware updates.