- lower number of blocks found => bigger mempool => higher fees.
Suppose there will be less and less blocks found due to the design, will it be a problem in the future? Bitcoin's benefit for low transaction cost compared to other means may gone for the small transaction amount.
as I said in the last line, everything will be back to normal soon.
the way difficulty works (even in bitcoin cash with their emergency adjustment and all the difficulty manipulation) is that it adjusts itself based on the hashrate. the plan is to set it to an amount which leads to 2016 blocks be found every 2 weeks. if hashrate goes up, blocks are found faster and difficulty increases to slow them down. and if hashrate goes down blocks are found slower so difficulty goes down to speed them up.
under normal circumstances hashrate doesn't just evaporate suddenly. it may go down a little and it may go up a little so the "speed" doesn't change much.
but when something like bitcoin cash exists and miners can switch easily, hashrate can drop fast. but as soon as difficulty on BCH adjusts and it becomes hard to mine it and also when its price drops, they will come back, at least most of them and things will be back to normal-ish.