"why don't my large projects get off the ground". My experience is that often teams and client-teams get scared off when people present great ideas - but with large amounts of uncertainty.
I came into one meeting where the client was discussing an IT project with the client's IT department. The meeting seemed to go well, but afterwards, I was told "IT don't want to do all the discovery so its getting binned again; 5 years repeating this". I suggested that given my client was the expert on the systems, that they and I should do all the scoping ourselves, create the learnings and actually present a basic design to their IT team. After 6 months of this, we were able to get IT department to build the hardware solution we needed and get the system going!
.. a bit like getting kit up here: This pic is Mauna Kea, Hawaii, HI - the peak of the tallest mountain on earth: 4500m above sea level (it also has about another 10,000 BELOW sea level) - I took this 2 years ago