All of which have application to the geotechnical engineer and should be seen as another tool in your toolbox.
Please post in this forum if you have any questions about how geophysics can help with your specific problem, or help better approach a problem you often encounter. Post a problem and some information on the project and let the geophysics community see what we can do to provide you a solution that can help.
I also agree with your position. I think one of the fundamental reasons for the lack of geophysical application in geotechnical engineering is that most engineers don't understand what geophysics is (like it's some black box thing) and therefore simply have no trust in the methods or results. From the geophysical side, it hasn't helped having people out there doing MASW or SASW (or shallow refraction, etc.) and those people coming up with off-the-wall results that are presented as valid data when they (the erstwhile geophysicist) doesn't know what a reasonable result should be.
There also seems to be a major disconnect between engineers and geophysicists- the geophysicists know how to measure a lot of different things (like shear wave velocity), but MOST engineers don't know what to do with the data beyond simple reference to something like the IBC charts to pick a site classification. A lot of this has to do with the basic formal education. Few advanced degree programs in the U.S. (elsewhere??) attempt to integrate any discussion of geophysics or geophysical data into engineering analysis, and the result is predictable.
How to fix this? Good question. We can try education. I've given several talks at regional engineering conferences in an attempt to educate people about geophysical applications in geotechnical engineering. Examples of "how I found the abandoned and buried piping at my building site" or "how to get definitive modulus values for use in settlement calculations" seem to get some interest. In many locales, I think it comes down to finding an application where geophysics provides better (and more cost effective) information than conventional testing.
As was discussed in other postings, knowledge of geophysical applications for geotechnical engineering provides a very powerful set of tools that can often provide data and/or interpretations that one simply cannot obtain without geophysical data.