Realistically, IMO we passed that majic number a long time ago.
I'm oldschoo, so I came from way back when we were getting by with 1200s. Now back then there was a lot of concern about getting your packs to last, and we all did things (tuning, motor winds, driving style, matched packs) to get to the end of runs. Miraculously most of us did most of the time, though there was quite of bit of drop off for the last half of your race. Then 1700s came along... and off to the races with evergrowing numbers - and now we're at 4600s and it's accomplished nothing IMHO other than leave people in search of larger powerplants to run their cars. And personally, to an extent, I find today's cars no faster than they were back in the day - just able to do so for a longer period.
All I do see is lower motor winds to get the power out of today's packs, and nobody dumping at the end of their runs (if they started with a full pack).


I knew you were going there.
The biggest issue I have and see with this presumption is that way back in the day race length was primarily determined around pack runtime and motors getting hot from running at high speeds for too long a period. Since technology has cured the runtime dilemna with the large capacity batteries, and while brushless systems do run cooler than their brushed counterparts, unless someone comes up with some really weird way of liquid or nitrogen cooling electric motors (I'm only using those as examples) the simple truth is that theorizing longer races is still only going to result in killing motors that aren't designed to run for prolonged periods of time - sans totally redesigning the current formula of motor allowances (540 can limit) which will result in the need to redesign all cars to accept larger powerplants.

And thus you get into a whole slippery slope of where does it stop???....