Also in 20+ years in enterprises have never heard of firewalls being left unmaintained. I don't know how that would pass security audits, why such a critical piece of security architecture would end up in this state or how any in-house development would work given the constant need to make changes to it.
You end up choosing between a heavyweight "advanced" WAF (either cloud or on-prem) that requires lots of tuning and response, which most orgs can't do properly, or a lightweight cloud WAF with vendor rules that doesn't do much but hey at least it's easy to look after.
Re: enterprise WAF maintenance, I know this is anecdotal but I was a pentester for 10 years and I could count the "non-dysfunctional enterprise WAF setups" I saw on one hand. Were you in a role where you talked to the staff who looked after them or dealt with the alerts? Often the org lacked the insight to understand there was a problem. "We bought the magic security box, we applied the patches, what's the issue?"
https://accelerationeconomy.com/cloud/amazon-shocker-ceo-jas...
And the article you posted is about total spend not just infrastructure.
Initial onboard was 2 FTE for ~6 months.
We are now at probably .5-.75 FTE. Onboarding new sites, responding to “waf broke the site”, type things and doing exceptions (for pen tests and what not).
Not sure of the TCO, but I shudder to think what would happen if we didnt have it.
We have a lot of…old…java…
There are environments where this makes sense. Banks are the classic - they have the money, they care about the risk, lots of places have systems still on java 8 and take > 1 month to deploy code fixes.
The biggest practical problem in my experience is that it's almost impossible to keep good people maintaining an enterprise WAF. Anyone with a deep enough understanding of web app security and network infra to do the job properly will get bored in the role and leave. WAFs are usually barely maintained for this reason.
Another major issue is alert handling - there's nobody with enough context. The SOC staff usually understand nothing (not the vuln, not web, not the app). The devs don't understand the vuln and the security team don't understand the app so tickets go round in circles with nobody able to understand if an alert is an FP or an actual issue. Eventually alerts start getting quietly dropped on the floor.