Well I think I have no choice but to try again. And again, until I get it right. After thinking (obsessing) over what I did, I think I have it narrowed down to a few key points.
1. As previously stated, the butter may have contributed. I think I remember my Grandmother making shortcakes with butter, and they never rose much.
2. Even if the butter might have worked, I don't think I "worked" it in enough. There were still some lumps of butter. I mistakenly thought that was supposed to be the case, like in rolled biscuits to create layers. Obviously not with these drop biscuits.
3. Colder fat. The butter had sat out for a while and it was getting a little soft.
4. I may have over mixed the dough. I was pretty careful to just mix enough to bring it all together, but then I realized I'd forgotten to add the salt. So, I had to mix it all again.
I'll bite the bullet and buy some Crisco this week and give it another shot. And since I'll have Crisco, I might as well make some fried chicken while I'm at it. My poor wife, she absolutely LOVES fried chicken, but she's been trying to eat healthier as we're going to the beach at the end of the month. Apparently women have some phobia about putting on a bathing suit for the first time every year?