As always, these discussions will depend on your definition of "dead" and "alive".
If we can call a technology dead once no new business is built on it, then I think we can safely call COBOL dead (and the IBM 390x aka Z/OS platform along with it, for which "COBOL" is usually a proxy).
But if we say that anything still being used in production is not dead, then of course COBOL is alive and significantly more alive than many other things which are younger than it.
But this shouldn't really be taken as a positive point for COBOL or the mainframe ecosystem. It's simply a fact of life that organizations tend to stick with the first thing that works, and for the types of entities involved in the first wave of digitalization (e.g. governments, banks, airlines) that was usually an IBM mainframe along with the software that runs on it.
If by new business we literally mean startups, then that has been the case basically forever, even back in the 60s and 70s. Mainframes were never really for new businesses in the startup sense of the word. The barrier to entry has always been kind of extreme. So the big customers even back in the day were always old insurance companies and banks and governments etc. It wasn't really until minicomputers that "new businesses" doing computing at all was feasible.
So in that sense, not much has really changed, and for the target market of the product, I don't think it makes sense as a good metric for whether the platform is dead or alive.
> we can call a technology dead once no new business is built on it
You don’t suppose any bank - or other large financial institution - might have standardised on Cobol for their core business flows/processes? In which case a new business-unit or “internal startup” team (e.g. a new category of insurance product) might very-well have some part written in Cobol so it integrates with the rest of the bank - or at very-least might be built-on-top of the org’s existing Cobol-running infrastructure (i.e. Not written in Cobol, but still runs on Z/OS because there’s no budget for buying new commodity x86 racks and the people to manage and run them).
COBOL is undead.
> and the IBM 390x aka Z/OS platform along with it
The problem with killing the mainframe is that no other platform really exists that can handle the amount of simultanous IO that you can get on a mainframe. Our mainframe easily processes 100m transactions per hour, with room to spare. And keep in mind that those transactions are for the most part synchronous, and will result in multiple SQL transactions per transaction.
Yes, eventual consistency is a thing, but it's a very bad match with the financial world at least, and maybe also military, insurance or medical/health. You can of course also partition the workload, but again, that creates consistency issues when going across shards.
Also, COBOL is far from dead, but it's slowly getting there. I don't know of a single bank that isn't actively working on getting out of the mainframe, though all projections i've seen says that the mainframe and COBOL will be around until at least 2050.
Give that a thought. That's 26 years of writing COBOL. Considering that COBOL programmers are also highly sought after, and usually well paid, one could literally still begin a career as a COBOL programmer today and almost get a full work life worth of it.