Currently there are again some XMR to grab 
Seriously, from my experience availability is "intermittent", i.e. normally if you try again after some hours often there are some available. And as they're working with their own reserves without purchasing liquidity, the relative shortage can be expected due to relatively few exchanges offering XMR.
XMR shortage may also be caused by the recent Kraken delisting in some European countries. Such delistings can lead to price drops of the XMR/USD price due to selling on the exchanges where the coin is delisted (because some users who have bought XMR for speculation usually don't want to bother with self-hosted wallets) without really having effect on the rest of the supply/demand equilibrium. This means that after such price drops the demand on other exchanges can drastically increase. It was extreme after the Binance delisting, but on a smaller scale, this was possibly what happened after the Kraken delisting too.
Seriously, from my experience availability is "intermittent", i.e. normally if you try again after some hours often there are some available. And as they're working with their own reserves without purchasing liquidity, the relative shortage can be expected due to relatively few exchanges offering XMR.
XMR shortage may also be caused by the recent Kraken delisting in some European countries. Such delistings can lead to price drops of the XMR/USD price due to selling on the exchanges where the coin is delisted (because some users who have bought XMR for speculation usually don't want to bother with self-hosted wallets) without really having effect on the rest of the supply/demand equilibrium. This means that after such price drops the demand on other exchanges can drastically increase. It was extreme after the Binance delisting, but on a smaller scale, this was possibly what happened after the Kraken delisting too.