Was Tyrell lying to Roy?
I think he's lying to Roy. SPOILER for Blade Runner 2049. Tyrell created Deckard and Rachael to fall in love and give birth. He is a god to replicants. He could have found a way or maybe even did find one to extend a replicants life, but chose not to give it to Roy. He may have been his exceptional son, but still a mere soldier. A maniacal murderer who'd only wreak more havoc once he is granted more time and only ruin Tyrell's achievements. When they both discussed ways to extend a replicants life, Tyrell gave him all the errors to hide his solution. Science is finding a solution between 5.000 errors and Tyrell managed to hide it from Roy. Roy, with all his skills did not recognize the lie and Tyrell chose to die instead of ruining his own legacy.