With Sia Prime calculating, in preparation for its airdrop, that some 34 SC addresses hold 57% of all SC, presumably all of these or nearly all being exchange wallets, I'm more convinced than ever that at least half of the ~3.7B SPACE airdropped were in exchange wallets and won't be claimed.
Of the half not in exchange wallets that could be claimed, I think no more than half ever will be claimed. This leads me to conclude that present circulating supply, including all coins mined to date (~906.6M) plus the 1/4 of the airdrop likely to be claimed, is only ~1.83B.
Compare to Sia's current supply of ~38B and this presents an attractive value proposition, with there being roughly 1/20th as many SPACE as SC currently circulating.