Regarding digging, you might find it funny that Indus valley civilization got discovered thanks to their bricks that the British found while laying railway tracks in North Western India. Those where being used as free and cheap but high quality ballast. So its indeed true in some regions one has to take care to miss.
Why, submerged dwarka is more important to Hindus than all those forts.
I have the strongest suspicion that there would be a significant population of people who self identify as Hindu but would have at best tepid interest. There would be people who would be unhappy that their taxes are going in that direction. Day to day mundane matters and relative importance of other artifacts according to their judgement will trump it (Dwarka).
From your comments in the thread it seems you are a shade touchy about Dwarka and were taking obvious metaphors literally, but I couldn't figure out how it (Dwarka) fit in what we were discussing in the thread -- lack of wide interest among Indians on historical artifacts. So I let it ('but, what about Dwarka') go as an instance of whataboutism.
My personal belief/opinion is that it makes a lot of sense to explore that(Dwarka) than throw money at the stupid idea that the geological formation connecting main land India to Srilanka is a man made bridge built by Ram's army.
Where I went to college in the US there was this house about a hundred odd years old. They would be absolutely drooling at that 'historic' artifact, there aren't as many (physical historical artifacts). People had a lot of time to care and funds to attend to it. Compare that with any run of the mill old city in India, or compare its capital, Delhi. It would be hard to throw stones far and not hit constructions that are 100 years old. The city is strewn with these and people are to busy fighting for their day to day needs. In such a scenario it is hard for the populace to agree that significant funds need to be allocated for preservation and restoration.
Add the political agenda to it that selectively directs the attention to artifacts that fit their agenda -- then this is what you get.