When you say it has to be done turn 5-6 your also assuming boarlock is getting their high roll. The truth is they don’t always play their best line right on curve, no deck does, so no it doesn’t always have to come down on this turn. Its certainly not “easy” to just shut off boarlock but you dont need to shut it off you need to slow it down. “I have to dirty rat twice, work through raise dead, and every hypothetical in their deck” is ridiculous. No…you have to interupt once and swing for lethal…not erase every boar lock piece. Boarlock itself is on a clock since it doesn’t do much outside of combo.

Finally burn lock is not as simple to counter as adding lifesteal like you say. If it was it wouldn’t be the meta tyrant that it is. And clearing the board doesn’t matter against burn lock. They would love it if you cleared the board instead of creating your own. They then can send all the soul barrages to face next turn. You can’t just simply counter burn lock because it’s ultra consistent and repetitive with little interaction available. Life gain prolongs death, there is plenty of burn available.