See, usually you don't have 11 developers coding 24/7. What you usually have is project managers, account managers etc and then a few people who code every now and then. Then you have licenses and support costs.

You can't just code the website, zip the code and mail it to the client. They have many stakeholders like this person needs to be able to show this that persin needs to be able to access this etc because they are running a business or service with than many people. Then you will have requirements like blind people should be able to use that and someone should be able to monitor all that. For each complication you will use specialized tools and do integration, i.e. Adobe will sell you one thing Oracle will sell you another thing and you will have to have people overseeing all these integrations and requirements etc.

That's why you have thousands of employees in tech companies with seemingly a simple product that you can fully code in a week(at least the user facing part of it).