MSTR is issuing stocks and debt to buy bitcoin, which means that those bitcoin belongs to MSTR stock and bond holders. Before ETF’s it was a proxy to get access to bitcoin so his model worked. 
Now there is no point in buying or holding MSTR as ETF’s are much more superior than a company stocks. It’s more better collateral than a company’s stock. 
Saylors infinite money glitch model only works if people keeps on buying his stocks and bonds, that’s the reason he keeps on shilling his company on news interviews. I haven’t seen any billionaire going on news interview that much.