What is your purpose in leaving your children such an inheritance? That is, do you see it as play money? Money for them to pass on? Do you see them with a lavish lifestyle? Do you picture them as philanthropists? Are you leaving them properties that require significant upkeep or primarily assets?
Another way of phrasing it: why do you feel an obligation to set your children up to be in the top <5% of US households? And that is assuming that you haven't set them up to do at least as well as yourself (or see them choosing different paths that won't lead to the type of accumulation you have achieved).
Once you can answer those questions, the follow up would be is there a better way to achieve those goals?
One reason I ask is because most people I know who have worked their way up to your level are freaked out at the prospect of leaving that much to their children and are off looking for charities or trust structures to mitigate the impact. Or suddenly spending a little more on themselves.
I just want to thank you for the considered comment. I feel an obligation to leave my children as well off as I was or that I will disappoint my parents. Also, I believe that with the large federal debt economic growth will be lower so i will be more difficult for my children to attain our standard of living.
As well off as you were at what point in your life? It sounds like you and your DW both grew up without much, and the wealth has come later, either because your mom married well, or through your own hard work/savings, or both. So do you want your kids to be you at 18, or you at 50? There's a difference, right? And even right now, your kids have a better start in life than you did at their ages, right? So how could that possibly be disappointing to your parents? Is it reasonable to expect that your kids should have at 18 the lifestyle you didn't earn until 50?
I would focus less on the financial situation at any given age and more on the life skills that earned that position. IOW, maybe you are where you are at 50 *because* of where you were at 18, not in spite of it. That is certainly true with me -- as much as I resented my much younger brothers getting free rides to college courtesy of the Bank of Dad, they also took those privileges completely for granted and screwed around too much. 25 years later, I am the only one in a position to RE. That is not a coincidence. Growing up with nothing taught me early that I was on my own and needed to earn whatever I wanted, save aggressively if I ever wanted to be secure, and spend wisely. My brothers didn't get that lesson until much, much later.
Not saying that giving kids money and privileges necessarily screws them up (my DH also had a free ride courtesy of the Bank of Dad and did just fine). But the point is rather that simply providing kids a specific sum of money will not guarantee they use their powers for good. So why work for X more years when you are already at a level that would leave your kids more than amply provided for if you died today? All the focus on specified dollar values is the tail wagging the dog.
For me, I am making sure my kids have college covered before I quit. College costs are quite dramatically higher than when I went, and so to know I can cover my kids' education and set them off in life not weighted down with massive debt is critically important to me. I am also using my own money to fund a Roth for them that matches whatever they earn from paying jobs, because compounding. Other than that, I am not planning on working longer so I can try to leave them a specific sum. My kids have grown up knowing they will need to earn their way, because while we make plenty of money, we do not make enough to set them up with a trust fund to support them in the style to which they would like to become accustomed. So I *hope* that they will use their college degrees to go get jobs and support themselves in a reasonable, sustainable lifestyle, so that even if we blow through all of our savings, they will be just fine; OTOH, if they do inherit something (more likely), that will be a nice bonus that helps them cover college for their kids, so the grandkids get to start off with the same advantages we provided their parents.
Tl;dr: what you teach your kids while you are here is infinitely more important than what you leave behind after you are gone.