The beauty of the THORChain lending design is that the RUNE that was "burned" to secure lending increases caps as RUNE outperforms the assets you can lend against (ETH, BTC). If RUNE spikes to $18 (3x's) and BTC/ETH climbs 30%, it opens more lending. If RUNE continues to outperform, lending will remain an option.
Of course, it is a bit of a chicken / egg scenario. If caps are raised, RUNE will rip. If caps are full and RUNE is stagnet, it doesn't have as big of a reason to outperform BTC/ETH.
In theory, the RUNE that has been burned could be all that is required to collateralize lending forever... it is wholly contingent on RUNE price action.
RE: Sell in May go Away?