It does a lot more than that. Many of its effects have no diminishing returns over time.
Your daily maximum limit is roughly 400mg. You can use more on rare occasions. Also using soda as an example is dubious - caffeine is not the reason you should limit your soda intake.
If they were selling this as a nootropic, you would be correct! Theanine aims to sedate thoughts and prevent repetitive motions (your body telling you to exercise). This is for the express purpose of breakfast, which demands a physical stimulant as well. The ratio being 1/2:1 (or rather, 1/4th the normal theanine for 150mg caffeine) will provide just that. Maybe the theanine could have been a little more, or a little less, but that will come down to you supplementing to your preference.