The bitcoin fees required for confirmation in the next block are currently above $20 for a typical transaction size[1]. This could be attributed to the block size limit, but recently the fees on Ethereum (which has no fixed block size limit) have exploded and are also well above $1 now[2].
So is the effect of deflation on spending even relevant at this point? We're learning that current blockchain designs don't scale, so widespread use of them as currency is impossible anyway!
Yes, there is R&D being done to try to address this, but it isn't clear to me that the problem can be solved while keeping the salient properties of cryptocurrencies.
[1] https://bitinfocharts.com/comparison/bitcoin-transactionfees...
[2] https://bitinfocharts.com/comparison/ethereum-transactionfee...