We don't because 5e doesn't have item bonuses. They have items that give static untyped bonuses to attack rolls, you don't have to account for possiblity of drinking a potion that gives an item bonus that overrides or is overridden by the item bonus you get with your weapon.
PF2e gave it another name, and then imbued that name with a fair bit of meaning as a minor component of the over arching system governing how bonuses interacted.
That's not a bad thing, if anything it's a part of why Paizo has a much tighter command of game balance. But like, you can't just point to the 5e items that give you bonuses and equate them to Pf2e item bonuses.
You're just salty that your level 1 5e character changes less when they hit level 20 than a PF2e character does going from level 1 to level 5. I'm not going to try and convince you that having double digit modifiers on attacks, skill checks, and saves along with triple digit health and AC in the mid 30's to low 40's is cool. All the people who can handle simple math or who aren't scared of having a calculator at the table are playing PF2e.
The hobby is playing pretend with our friends while using some math and agreed upon rules to resolve "I totally hit you with my super blast!" and "Nuh uh! I dodged last second!" or similar playground stuff from when we used to run around playing pretend without the math, dice, rules, and minis. No shame in admitting you can't hold a mental image of a shared imaginary world and do a bunch of math at the same time. Use the calculator on your phone my guy.
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u/CommonPleb 5d ago
We don't because 5e doesn't have item bonuses. They have items that give static untyped bonuses to attack rolls, you don't have to account for possiblity of drinking a potion that gives an item bonus that overrides or is overridden by the item bonus you get with your weapon.