The "6-8 encounters a day" thing wasn't an issue.
The "issue" was that 5e assume that your DM was game designer and D&D veteran who did not need any additional rules or advice in order to adjust the game to a different amount of encounters and had the authority to change the rules willy willy without testing or player buy-in.
The "issue" was that 5e assume that your DM was game designer and D&D veteran who did not need any additional rules or advice in order to adjust the game to a different amount of encounters and had the authority to change the rules willy willy without testing or player buy-in.