Well, the reason for having these lockouts is simple: longevity. If people can just keep farming the bosses every day, every hour, they will 1) gear up pretty quickly, 2) will be sick of the whole thing before long. Devs want you to keep playing longer. Hence the mechanic that only allows you to defeat an operation boss once a week.
I agree with this, and I mentioned this above. The question comes down to Fun VS Longevity of the game VS. Stress.
But when 8 to 16 players spend a whole night trying to do something and it never happens. Then try again the next day and it never happens. I'm sorry. That's just wrong, and you can't justify your money's worth.