I'm not so sure the Kona is all that much thicker anymore. I was looking for exactly the same thing, a nice weight White Kona Cotton. I too walked out, without spending a dime. Very sad indeed.
I find ALL fabric is starting to be very thin, no matter cost or the mfg. CHEAPLY MADE. Once we lost our USA mfg we lost quality. I recently came across some older fabric I've had for a really long time. It is WAY better quality then anything I have in my current fabrics. Clothing is the same. Cheap, stretchy fabric that pills up and looks badly after only a few washings.