>> The alternative is to list on a pink sheet exchange

Nah, there's OTC which is different than pink sheet. There's a couple of levels of OTC above that, between the pink sheets and the exchange traded stocks.

Plenty of OTC stocks have graduated, plenty of respectable stocks have gone from exchange traded to penny stock status and back.

Pink sheet stocks though? I don't know. Who buys those? Postmen? There's always postmen.