It is not only not that much more complex, it is often less complex.
Higher-level services like PaaS (Heroku and above) genuinely do abstract a number of details. But EC2 is just renting pseudo-bare computers—they save no complexity, and they add more by being diskless and requiring networked storage (EBS). The main thing they give you is the ability to spin up arbitrarily many more identical instances at a moment’s notice (usually, at least theoretically, though the amount of the time that you actually hit unavailability or shadow quotas is surprisingly high).
Higher-level services like PaaS (Heroku and above) genuinely do abstract a number of details. But EC2 is just renting pseudo-bare computers—they save no complexity, and they add more by being diskless and requiring networked storage (EBS). The main thing they give you is the ability to spin up arbitrarily many more identical instances at a moment’s notice (usually, at least theoretically, though the amount of the time that you actually hit unavailability or shadow quotas is surprisingly high).