Before GPS, we struggled to find precision approaches to fly for practice and testing. Now, the opposite is true since flying the vertical guidance on GPS approaches is ILS-like.
As we move forward in time with the proliferation of LPV approaches, the phaseout of non-precision approaches using ground-based navaids such as VOR, NDB, and LOC-only will result in fewer and fewer non-precision approaches. Furthermore, some WAAS navigators often provide an advisory glideslope to non-precision RNAV approaches: LNAV+V and LP+V. The “+V” refers to the advisory glideslope. An LP (localizer performance) approach is a non-precision RNAV approach that requires WAAS. Bottom line: there is almost always an electronic glideslope lurking in the shadows.