Here's my blunt response: Yes, if you insist on owning 0-3-year-old cars for the rest of your life, the monthly payment may be less if you lease instead of buying. But if you're looking to optimize how much you can invest, leasing or buying a new car are both terrible choices.
Here are a few things to keep in mind when you have such conversations:
1) Your net worth is over $1.6 MILLION DOLLARS. And you're just middle aged. And you're doing it on a single (albeit high) income. The results stand on their own. Are your peers in a similar position?
2) Saying "I'm leasing so I have more money to invest" is an attempt to rationalize a poor financial choice. It's like saying "I play blackjack instead of the slots, because the payout percentage is higher." New cars are financially suboptimal, regardless of whether you buy or lease. If your coworkers were actually looking to increase their retirement contributions, they would save up, buy a good, reliable, economical, used (GREU) car, and then invest their excess cash flow.
2a) They'll be leasing forever. Pay cash for a GREU car, and your excess cashflow will very quickly make up the difference. The math is simple enough, and the payback period fast enough, that you can do it in your head. Pay $500/mo forever to lease, or save up for a year and pay $6k for a GREUcar, and then have $6k/year to invest for the next 10-15 years.
2b) Even if you purchase a brand new car and finance it, the loan will be paid off eventually, while your coworkers are still paying a monthly lease.
2c) Don't forget the significant insurance cost savings from driving a GREU car instead of leasing.
3) There's nothing wrong with re-evaluating your choices when presented with alternatives, but remember that your current choice may still be the best for you.
4) You are only privy to a tiny sliver of your coworkers' financial situation. You don't know how much they have saved for retirement, or even if their hypothetical savings from leasing are actually being invested.
5) On the house front, their chosen path may be the correct one for their situation and risk-tolerance. It is mathematically optimal to make a minimum down payment, and stretch out the loan as long as possible, if you invest the difference, and if the stock market returns over the same period are greater than the interest rate. But that's not guaranteed.
6) Your values and goals can be different than your coworkers', and this difference can lead to different choices which are right for each person. Most MMM forumgoers are here because of a shared interest in early retirement. You and your wife appear to value avoiding debt instead of optimizing your investment contributions, and value investing over consumption. Your coworkers may value driving a new car over early retirement. In MMM land, that's crazy talk, because we recognize that the fancy gadgets on new cars don't significantly improve our happiness.