Definition of summit-fi is when the mids are a literal summit

Yeah, you got it basically right! You missed a few of the more specific wording used, but that’s honestly OK and not essential for understanding :-)

If you do a 1 to 1 translation you’d probably end up with “Here, my son of a bitch! Take this perfect product, of course it’s identical to the first model! That’s because the first model has been perfect for the longest time!”

Tricky words here being ‘längst’ and ‘nämlich’ because they don’t have a direct english counterpart. Also keep in mind that the original comment isn’t 100% grammatically correct… Hope you learned something :-)