These days most organizations will not tolerate just copying files over. There will be a process for testing the code and then stuff will probably be put in a container, to be even easier to run on another server.

At that point the advantage of just sftp-ing files over disappears. It is no longer deemed safe enough to do so. Usually it is not the end of the world, if your website is down for a minute, but it does tarnish the public image of reliability, so organizations are not willing to put up with developers making a typo somewhere bringing down their website or causing at least an annoying error on the website.

Instead of copying files over to another server, you would typically do some docker pull or other container engine pull some image or what have you. Then you would run that previously tested thing on the server.

There is a whole range of projects like that out in the wild, once you leave the realms of startups and big tech.

It's about as easy to do "proper" deployment using bundles / containers / CICD / kubernetes / gitops with PHP as with any other stack. It's also possible to click a wordpress domain for $10/month and upload 2 php files and start making revenue.

For a small business that is starting up, choosing between $10k of freelance work to get a nice github actions workflow on GKE + a monthly retainer of $2k for "maintenance" vs a one time $1k of freelance work to get a wordpress where you can configure the plugins and theme yourself is a no brainer. Many of those small business then grow much larger and reach a point where in hindsight you can say "should have gone with docker containers". But the original decision was not just perfectly valid, but probably the only reasonable one.