It's complicated, but you're right that you're not as well off as a true level 80 character.
Your attributes are scaled up to what they would be if you were level 80 (916 in each attribute). The footing is perfectly even for this aspect.
Your equipment is scaled up to have the same relationship to a level 80 character that it normally has to your level. So if you have a green-quality chest piece that's 2 levels lower than your current level, it's scaled to give the stats of a green-quality level 78 chest piece. This aspect can actually favor lower level players (since it's easier to keep your gear level appropriate at lower levels than at higher levels, until you hit 80) if they have very good gear for their level, but most people who are serious about equipping their level 80 characters will have rare (yellow) or even exotic (orange) level 80 gear in most/all slots, which a lower level character just won't be able to match.
You don't gain any trait points. True level 80 characters will have more trait points than you, which means they'll be getting more attribute bonuses from traits than a lower level character will.
TLDR: Yes, you and your equipment are scaled up to their level 80ish equivalents, but true level 80 characters will still have better attributes than you thanks to having better gear and more trait points.