The answer to this question is not easy. Holistic security is the only answer. If you're going to be Internet-connected, you need both, plain and simple. There are ways to minimize exposure but you need to understand threats and how they pertain to what's important on your network.
If you try to rely exclusively on endpoint protection, what about your devices that don't/can't have endpoint protection? ...printers, cameras, phones, etc. are examples of devices that are commonly exploited in a network where you probably can't layer on endpoint protection.
Conversely, a firewall only protects you at the boundary. Once an attacker is inside, they often have uninhibited access to the internal network and can then laterally move or escalate to effect whatever outcome they're after.
Each business needs to understand what's important for their company. An ecommerce site has their intellectual property (IP) out in front of the world. So they leverage reverse proxies, firewalls, code reviews, as well as host-based protections. A political organization where the users and their information are important would probably focus more heavily on email encryption, attachment sandboxing, disk encryption, AV/AM solutions, etc.
The real answer is that there is no one panacea for security. It's all about evaluating risk and leveraging resources according to what's important to each organization.
My personal opinion is that architecture is the best answer: for non-ecommerce companies, keep everything you can on a closed network that never touches the Internet and for those services that require it (email, web, etc.) that be accomplished in a thin/zero client, non-persistent OS that doesn't have access to the corp net. Any files that need to traverse the Internet-to-closed-net boundary be done by IT staff via a very deliberate process (download, scan, compare hashes, sandbox, move to closed net). This suggestion has its limits but considering the ratio of attacks and vulnerabilities originating from being connected to the Internet, cordoning it off as much as possible, in my opinion, is the best answer.