For the simple case of electron-positron annihilation, they transform into high-energy photons, whose total energy is equal to the total mass-energy of the electron and positron. See: https://en.wikipedia.org/wiki/Electron–positron_annihilation

These are famously common bugs across games in all genres running on all kinds of different engines.

Correct, but we aren’t talking about them. Whataboutism isn’t constructive.

I’d go so far as to not even call them bugs because computers simply don’t have the power to calculate collision down to the picosecond/picometer.

Actually, a large proportion of OoB clips in games are due to some combination of lacking speed caps and having acute angles in collision boxes.

Every game that’s ever been made has sacrificed precision in physics for performance.

Correct, and I’m not disputing this.

Perhaps the reason it’s more noticeable in Bethesda games is because they typically have way more persistent, physics-enabled objects.

This definitely contributes to the issues common in Bethesda games, but it’s not the only reason. Take Skyrim for example: some of its best-known glitches (such as restoration bonuses buffing enchantments, the various duplication glitches, and basically everything involving horses) have nothing to do with the number of dynamic objects loaded.

That’s actually a strength of the engine, and something no other developer really even attempts.

Not really - plenty of other games use Havok physics and don’t suffer from the same issues, or at least not to the same degree. Perhaps there’s a reason other developers using the Havok physics engine don’t make games with huge quantities of dynamic objects loaded at once.

Oh don’t get me wrong, Bethesda games are generally great (with notable exceptions like Fallout 76), and do phenomenally well in sales. However, dismissing any and all criticism of the games’ numerous flaws (including glitches which often carry over between subsequent titles, like clipping through collision boxes and falling through maps) is willful ignorance at its finest. Every Bethesda game has performance issues and game-breaking bugs, and there was no reason to expect Starfield to be any different in that regard.

People figured out the performance issues with Starfield when it was first announced: the Bethesda logo