When I used to do black & white and enlarged my photos to 20" x 16" or larger, the standard zoom lenses produced poor results, and I had a medium format 120mm camera with a range of lenses. My portrait lens cost over £900 some years ago, and it's all unsaleable junk now.
The big change is the sensor in digital cameras, which just don't need super quality lenses. The weak point used to be the lens - now it's the sensor.
If you're not shooting bigger than A4 or 10X8, it's not worth going for a DSLR.