Making tea well is hard.
Some teas become bitter and ruined if steeped in water that's too hot. Green tea, for example, is fine at 65 degrees but not at 75-80.
The only way to get this right is to use a tea thermometer. But some tea thermometers force you to heat more water than you'd like, because otherwise they don't immerse properly, giving you the wrong reading. You then have to measure the quantity you need, and throw the rest away.
And heat the water slowly, in simmer, not high, because high makes it very easy to overshoot your desired temperature and ruin your tea. If your tea thermometer is showing 60, it may be much higher, like 70, producing a bitter brew.
To evenly heat water, it's also best to use a copper-bottomed vessel, which conducts heat evenly.
In addition to heating the water to the right temperature, you should steep the tea for the right duration for the tea. Steep it too long, and the taste won't be as good. Steep it too short, and it won't even infuse.
See how complex making tea is? What can we do about it?
Let's apply a lesson from a related field: coffee. You can buy ground coffee at the supermarket, but it's not as fresh. Coffee fans buy beans and grind them afresh each time. But a company named Keurig came up with an ingenious solution — selling single-use cups containing ground coffee sealed in nitrogen. You feed one into a machine, which punches a hole and makes the coffee. Since the cups are single-use and sealed in nitrogen until use, they don't become stale. The company quickly reached a billion dollars in annual sales.
Applying this lesson to tea, companies could brew tea at the right temperature for the right duration, in the smallest amount of water possible. They would then sell the concentrate in small, single-use cups. When you feel like having tea, you open one and just add hot water. A cup of essence would be appropriate for one cup of tea, which is 237 ml.
If steeped tea spoils soon, the concentrate could be sold frozen.
This takes the hassle out of making tea, while still giving you perfectly steeped, tasty tea everytime.