I've recently heard Elon Musk talking about a supply chain shortage of large step-down transformers. This large component is typically installed by the utility company and most everything after that is Tesla equipment to convert what is typically 480VAC into DC for fast chargers. So without the installation of the transformer, progress of the SC site would pretty much be at a standstill. This is just speculation on my part, as a possible cause of the delay in progress at the Destin site. This is typically a 1000KVA transformer that converts 7.2KV primary -> 480V secondary which is what Tesla needs to work with its equipment. Most of the Tesla equipment is prefabricated and can be installed very quickly. If interested, here is a link to an informative video of a guy describing a typical
prefabricated site layout.