You reminded me of my situation when I was in my 40s, ten years ago. So I am inclined to agree with you that on the average, a dual income family where both husband and wife are working professionals, will be able to accrue a net worth of around $2.5M by their mid 40s. I am just a little surprise that this amount hasn't gone up much from a decade ago.

Then my wife and I set ourselves a target to save $1m each (excluding our home) by 55 at which point we will retire. We achieved that last year at 53. We raised the bar to $1.5m each. At our current savings rate we are confident to reach the target next year at age 55. Including our home, our net worth will then be $4.5m

In your case, you can achieve $5m, if you can accrue over $200k savings per year till you reach 55. It is very possible especially if you have other sources of income eg dividends from stocks, rental etc..