God, presumably, is eternal. Never ending. Eternity is a reeeeeely long time - but let's give it a number. The Earth is - according to the Bible - some 6,000 years old. Let's add a few hundred before that, and lets also assume that eternity is going to go on long after the Earth ends as per the Revelation. Call "eternity" some 20,000 years - no way is that eternity, but it'll do.
God spent 30 years of his 20,000 year existence on earth, with no status and living as a commoner. 0.15% of his span of existence. To a 3-score-and-ten human, that's the equivalent of about 38 days. So what they are calling a sacrifice is the equivalent of a king choosing to live amongst the common people for just over a month, enduring hardship and pain....but then returning to his castle and all his power and status and priviledge at the end of those few weeks.
Yes. It's a sacrifice, I grant you that. But as a period of total life, it's the equivalent of observing Lent ONCE during an earthly life. Nothing gets given up permanently. And, let's not forget, this is assuming a VERY small eternity of 20,000 years. Make eternity something more realistic - say, 2,000,000 years (which is still a mighty small eternity) and that 38 day equivalent becomes 9 hours - a longish working day. Make eternity something close to the age of the universe so far - some 13,000,000,000 years - and that "sacrifice" drops to the equivalent of something akin to 5 seconds.
The point I'm trying to make is that as a fraction of a being's total existence, the time "sacrificed" on earth was next to nothing. And at the end of that teeny-tiny period, ALL Christ's power and status and wonder was resumed.
I'm not saying that it was a pleasant experience for him. I wouldn't be thrilled at the prospect of spending 6 weeks in a famine-struck village in central Africa where they spent the last week beating me up. But if at the end of that week I went home with all my injuries healed, and with the knowledge that I'd helped a lot of people of my own volition, then I'd count it time well spent as I returned to the next 30 years of soft pillows, clean water, and good living.
Sacrifice? Yes. Sure. Just not a particularly big or meaningful one. For god, the equivalent of (for one single occasion in eternity) foregoing having sugar in his coffee.