Blockchain size and Transaction fees

Hey, So i've only recently started taking an interest in bitcoin after having heard a few friends buying into it. A couple of questions though.

If every single transaction is recorded in the blockchain, when/if bitcoin becomes "mainstream", won't the size of the blockchain/ledger become problematic within the network?

I've also read transaction costs also vary with demand? Could this create a problem where the bitcoin "1%" (could that be a thing?) can essentially buy up all the transaction queue, creating a tiered bitcoin society where the proletariat have to wait hours for transactions to go through?

If these are stupid questions I apologise in advance.