Why are suits so boxy?

I pulled out my $30 Kohl's suit this morning (it's kind of a low-end Nanette Lepore knock off) and decided it didn't quite fit right any more so I went to the mall to find a suitable replacement -- budget was $150.

I think the only people who must buy suits are shaped like big squares with really thick arms and legs. Which I know can't be true, because where do all those little cutie real estate agent types get their suits? I hunted at Nordstrom, Express, Banana Republic, The Limited, New York & Co., Ann Taylor, and Loft -- and first of all, I'm like trying on sizes 2 and 4 in blazers (which should never be my size -- I should be at least a 6 or 8), and all the arms are still way too big around!

I finally found a stylish suit at BR that doesn't make me look like a linebacker, with a sale price and additional 25% discount, but it's still not right. The jacket is cute and fits well, but the pants are way too high waisted and have a lot of material around the hips which really doesn't flatter me.

So, after playing dress up in my closet for the last hour, I think I've managed to pull together an "interview appropriate for the tech industry-but not for law offices or finance" suit that pairs the navy BR jacket with a pair of light beige Express Editors I already own (miraculously the same material style & weight as the jacket -- thank you random Chinese textile supplier who services American mall stores year after year!), and finished with either a plain tank or white button down, and navy blue Tory Burch revas. I look like I want to sell you a condo now.

(Pants in light beige, in real life)