My theory on why this is the case hasn’t changed since Tulsi joined the race, as I’ve written since she announced (I support Tulsi as a second choice to Bernie). There are still many people who remember the economics of the 60s and 70s and the huge change that started with Reagan. The results of which are really felt today. This makes Bernie’s call for a return to FDR style social democracy resonate.
Conversely, the MIC has been endemic to US policy since WWII. Meaning there are probably 3 voters in the US who remember a time before the military dominated the US economy. The MIC is far more entrenched than Wall Street.
Finally, the MIC is spread across the country in every state, and does actually produce tangible goods — not efficient or useful for the 99%, but it still actually employs a lot of people. Wall Street is concentrated in NYC, employs very few, and the people at the top are well known individuals. All that makes Bernie’s economic fight against the US oligarchs of finance much easier than the Tulsi’s fight against half of the yearly US discretionary budget being dedicated to war.