When economy is unstable people are less enticed to invest, so there may be a smaller number of new startup business and so there is less need for domains too. Last year and this one have been under the turmoil of US election but 2018 was expected to make a comeback. Now, Forbes journalist forecast less than 3% growth in US GDP for 2018. and that is a bit less than 2017. which is not good for domain business too.
On the other hand Russia and US are escalating their cold war, talk is that they both want to extract oil from Arctic (north pole). Domains with that conotation could be valuble.