Thickness difference in a container affects the manner of heat dissipation of the container itself and the content it holds. It is typical that mass-produced gaiwans, including all that I use for general purposes, have a thinner bottom and increasing thickness on the side wall towards the top. That is why the hand-thrown gaiwans are a lot more ideal, but they are way too expensive for daily use for most of us.
Anyway, your sample is illustrative of poor thickness distribution even for a mould cast production. This is likely a result of poor skills and/or management. Having said that, however, a lot of chinaware produced all around the world have the same characteristics.
It is likely to affect on the quality of infusion. One way to check differences is to control all other variables and use a few different infusion wares to conduct infusion tests on the same tea.
