Not exactly. Bonds hit 292 home runs in the first 10 years of his career (prior to any allegations of steroid use) and had developed into a serious 40-50 home run per season threat.
Figure 5 more years at 42 home runs, a falloff with the next 5 years at 32 home runs, and 2 "hangin' on" seasons at 20 home runs, and he totals 702 homers. With the numbers he was putting up at the end of his first 10 years, it was possible for him to reach 700 without any steroid help.
Note that you are defending a cheater.
It would be helpful if you could show any other hitter prior to the steroid era having similar power vs years. Your data is biased because you are used to these high HR seasons as a guide - 42 HR seasons consistently were not that common pre-1998 for anyone.
Bonds was a great player. Your fantasy analysis sort of assumes he was the best to ever play. He never did what you suggest - he cheated his way to 700 - he should be regarded only for his actions as a cheater.
Interesting theory ... but we'll never really know for sure now, will we?
This is where I think your estimate is way off. I'm not sure I would figure "five more years at 42 home runs" for a guy who averaged 30-35 for the first ten years of his career and had only reached the 40-HR threshold once in that period.
I would look at it a different way. Take his career up to 1999, which is the last year his home run totals bear any resemlance to a "normal" career trend. At that point he was 34 years old, had played 14 seasons, and had 445 home runs. If over the next five years he had seasons that were consistent with his average for the first 14 years, he would have barely reached the 600-HR threshold by the age of 39. Without steroids, I would question whether he would even be able to play much beyond that, and if he could even reach the 25-HR level even once more, let along four times.