Large, widely held stocks sit here because index funds and custodians hold enormous inventories that are rarely fully lent. Fees are a few basis points, the locate-requirement is satisfied by the list itself, and a share-recall is unlikely.
The list is a snapshot published each morning and is not a promise. A stock can move from easy to hard-to-borrow intraday on a news event, and the fee on an existing position changes with it rather than being locked at entry.
Example: a mega cap shows a 0.30% borrow fee. Shorting $200,000 costs about $600 a year, roughly $1.64 a day, small enough that fee is not a factor in the trade.
Related: hard-to-borrow, locate-requirement, borrow-fee, securities-lending, short-selling