There should be easier way, e.g. in Azure you can start WordPress (includes MySQL, limited to one app service instance) with one click, not sure what are the costs of maintaining that, but at least starting one in that case is pain free.
True, although ongoing maintenance of a CloudFormation template isn't significant. It's essentially a specification of the state of the infrastructure, which AWS is then responsible for making come true. It's also their stuff from CloudFormation back, so they're on the hook for making sure nothing changes that would break it (relative to Terraform or other alternatives).
Also keep in mind that AWS services are usually encapsulated from each other, which is a good thing. The result, though, is that defining something like this involves a lot of parts. You need to define its private network, its subnet masks, its EC2 instance types, its database type and configuration, etc. The author also took it a step further to define CloudWatch alarms and scaling policies, which is great.
It is something that requires understanding if changes are necessary, but it's not something that you would expect to need tweaks over time.
> There should be easier way
There is--he could have started Wordpress by just launching an instance with userdata that installs it and sets it up. This isn't really comparable to that because it involves multiple servers behind a load balancer, a CDN, a hosted DNS zone, a separate relational database service instance, and autoscaling.
Sure you can click to set up WordPress on other hosts.
But how do you scale capacity of the servers or the database? How do you peer the network to your other cloud resources? How do you mirror the stack in another region?
With CloudFormation resource management is a few API calls away.
You can also use CloudFormation in point and click mode to create a stack and update its resources.
It may be overkill for some cases but for serious systems it's the best practice.
Maybe that is from having been through the ad-hoc or "well, its easy to spin up, but this only works for a single node" setup roundabout a few times.