Granted, the property is public, leased to a private enterprise.
Actually, SI was mainly "built up" (it was already a natural shoal) by
the dredging ops of the Navy during WWII (to allow SD Bay to take in
carriers. The 1950's saw expansion of this dredging to bring the
island 7 ft above mean high tide.

But what does this have to do with the price of tea in China? The
original thread was about how "Meigs now enjoyed by all." You
parallelled the gov't 'rezoning' Meigs as a concert venue with SI. SI
is not a really good parallel...The land is leased by the port
authority to various hotels, eateries, and private marinas. What makes
you think that (aside from rent and use taxes) that San Diego sees any
money from what happens at a concert venue? What the leasees do with
the land is the lesee's business (subject to the lease
restrictions/zoning/etc, of course). The only monies that the Port
district of San Diego receives from the activities on the island a
Lease (OK, I admit, there's probably some good money on prime
property made here. However, with the City Attorney looking into the
terms of the more than 600 leases, I would not be surprised if there
weren't some bad dealings here....)
Sales Tax revenues (IIRC 7.25% in city of SD)
TOT revenues (10.5% in city of SD) (This is probably why there are
mostly hotels on the island)
I don't know if there is any tax on moorings in the various marinas.

San Diego does not see one penny (aside from sales tax and possibly
permit fees...which actually could be waived as one of the terms of the
lease!) of revenue from the concerts in a private venue like Humprhy's.
That'd be like saying that the City of LA started realizing money from
the concerts put on at the House of Blues.