I assumed sysfs exposes a subset of available information: that pciutils can expose more data given hardware support. I know some of the more basic pciutils ran on my computer, though.
FWIW, pciutils can use a variety of different access methods. Use lspci -A help to see the different access methods, and then lspci -A $method to use a different access method. Note that one of the access methods on linux is linux-sysfs, so pciutils can use sysfs under the hood.
