Just ballparking the value of the house at around $1.5mil (you said last year, which I'm averaging out an interest rate of 4.5% and then rounding down. Assuming a 30 year mortgage) then in 30 years time, you'll have an asset with a value likely to be greater than $1.5 million.
Assuming you eventually have children, they may inherit this asset. That is wealth, and that wealth will transcend your generation.
That covers the literal definition.
On the other hand, the people who are lifetime renters will have spent (assuming rates stay static, which is unlikely) just over a million for which they have received no assets.
Your assumption is that they're pocketing $500k, and are ahead, but even if we ignore that their rents are likely to rise, while your mortgage is likely to stay the same, and the most likely outcome is that rental rates increase over time. Likely double. At which time they'll have spent the same, or more, or maybe slightly less, but still have nothing.
Meanwhile you'll likely make improvements, perhaps refinance if and when rates are lower, and the value of your home will almost certainly increase as well.
No doubt that it'll fluctuate in the meantime, and for sure there are plenty of maladies that can occur between now and 30 years from now, but at the end of the day, comparatively you are building wealth and stability for someone to inherit (or for you to capitalize into dollars, which is also inheritable) while lifelong renters are not. Assuming no meaningful changes (a big assumption) you will likely end up $3 million ahead of the renters on this timescale.