also find this quite ridiculous 
how are old transactions cheaper when btc was less inflated and there were less miners
Transactions were cheaper because there were less transactions. Blocks weren't full so there wasn't any fee pressure and thus you didn't really have to pay any fees. That has nothing to do with inflation or miners.how are old transactions cheaper when btc was less inflated and there were less miners
if i'm not wrong, one of the aims of cryptos were to reduce to cost of transactions but now it's getting almost on par or even higher than traditional currency transaction fees. 
You are wrong. The purpose of creating Bitcoin was to create a money system which did not rely on a central authority. It was not to create a global currency that had cheap transaction fees.