Is a low-resolution scan of B&W negatives expected from a drugstore?
Yes, it is a drugstore and not a photography store.
Is this impoverished?
Yes, 1215x1800 is a low resolution.
Do I need to find better scanning technology than Walgreens?
I do not know, that is dependent upon your needs.
I recently had a batch of 35mm color negatives scanned and received JPGs at 4187x2776 which is a much higher resolution than the scans you received from Walgreens.
If you require a higher resolution I recommend you shop around. I chose ScanCafe and for me it took about two months for them to turn around 600+ color negatives at around $.28 a negative. I feel it was worth the money and time as the scans are of high quality and I can comfortably crop and edit them for use in print and the web.