I don't know where they get this number:
https://bitcoinfees.earn.com/At the time of writing, the optimal transaction fee for a 95% chance of getting into the next 3 blocks is 270 sat/byte.
An average transaction is still 226 bytes. This comes to an optimal transaction fee of 61k satoshi's, that's 0.0006 BTC = about $5 at the current preev rate.
If you use a segwit wallet, the fee is a lot less, if you're willing to wait longer than 30 minutes (on average), the necessary fee also drops.
The only way to reach a $70 transaction fee is by using a massive amount of inputs/outputs, not using a segwit transaction and overpaying your fee
Anyways, 5 USD is not the acceptable level either. And the rise of bitcoin price is no excuse here - with higher price, the miners should be happy to get equivalent USD fees, i.e. transaction fees should be accepted even in lower in BTC
I do have to agree with you that $5 is to much... But miners are running a business. They make about 2,5 BTC/block in fees (at least, that's what i calculated a couple weeks ago). If they have sufficient high-fee transactions, there is no incentive for them to pick low-fee transactions and lose out on these fees.
You have to realise nowadays, most miners are no longer idealists who mine to decentralise the network... Nowadays, the bulk of the miners are big companies that invested millions in ASIC's, and they want to make a profit (since this is their job, they do it to support their families, and the families of their employees).
Even if the miners would pick, let's say, transactions with a 10 sat/byte fee, while there are 270 sat/byte transactions sitting in their mempools... Do you think the people that payed 270 sat/byte would be happy? They payed a lot of money to have a decent shot at getting a fast confirmation, i guess they would be pissed off if they saw block after block being broadcasted filled with low fee transactions while they were still waiting to see their high fee transaction end up in a block...