Monero has a adaptive blocksize calculated based on the last 100 blocks. If demand increases the blocksize will increase as well. But there is a limit to the size.
Discussion
From what I understand even with max size the transaction rate if the network is limited and won't support mass adoption
I highly doubt we will see any form of mass adaptation in the near and not so near future. But I'm confident if we will come closer to this point, a solution will be found.
I heard there are considerations building an off-chain payment network (2nd layer)