Because sacrifice in general doesn't make sense with how mass scales. The only situation where you might have a spike in mass income which can lead to overproduction of bp and in turn a reason to sacrifice is going to be when a map has absurdly massive mass reclaim but nearly no mexes and the match goes super long. I struggle to think of situations where this happens since even Ditch 1v1 still has a solid mex basis for you to continue to use your engies.
Otherwise what situations exist? You have a gc 30 seconds from completing with current bp. It says it is 90% done. You have 30 t1 engies and 3 t3 engies. What do you sacrifice and how much to beat the ml 10 seconds away? No one is going to do the calculations, they'll just emergency hit the button and hope it works because if they don't they lose. If the ml was 30 seconds away they won't hit the button. Why would they ruin their BP for slightly faster gc when they could use it to make the next gc faster or reclaim the upcoming battle?
Like literally the most practical use of sacrifice I have ever seen was Pepsi accidentally making 5 mex before hydro in a tournament and sacrificing his first 2 engies to build his hydro as he e stalled. He was still absurdly behind in the game because of it so it isn't anything that will ever be practical, but that's like the only time I've thought the mechanic added anything to the game. Maybe it gets buffed into the sky to make some tradeoff actually exist, I dunno.