The goliaths prooved to be useless, at the end of war a few thousands were still in stock. Volkssturm got all the spare parts in the first place.
Another thought: The Volkssturm was to be formed by the "Gauleiter". These were "district controllers" of the nazi party. Sometimes these 'district controllers' were also governors of their district, but in the first place they were heads of the nazi party in their district. So, this is like the Republican party of Oregon would have their own private army. Nominally these Volksturm units were subdued to the army, but the bonds with the local district controllers were much stronger.
Because these district controllers had their own power base in their district, interpersonal bonds. If a district controller was eager, he would contact local weapon manufactuerers and order to withhold weapons produced for army and SS. Then he could use these to equip his "Volksturm". This happened quite a lot in the last month of the 3rd Reich. While the central government got more and more powerless, these district controllers accumulated powers. Which, of course, toook its share in the rapid downfall.
This explains the different levels of equipment the Volksturm had, depending on the strength of their local district controllers and the economically situation in these districts.