I had to buy about 8 different brands of biking shorts to try on in order to find ones that weren't like tourniquets on my thighs. I'm not fat, but I do have some middle aged fat on my thighs- nothing 'abnormal'. The Terry T-short (long) and the Shebeest Ultra-D fit me great and didn't have the Elastic of Death around my thighs.

Yes, it is possible to find ones that fit right if you try on enough different brands and styles. I suspect most bike shorts are made with slim proportions in mind, not pear shapes like mine.