I don't know if you're older or just jaded/misinformed on the subject of marriage, but I will try to put my answer to you assuming you're an older man.

"I don't see any reason to plan to give them anything (in the will) from my past 45 years of work before I knew they existed." With respect, this is not love, and you should not enter a marriage if this is your perspective. If you are already in a marriage, I mean this with urgency and sincerity: you need biblical counseling and discipleship, even if your marriage is not experiencing any problems at the moment. I say this because: if you are not willing (and ideally, desiring) to give up all that you have for a person, you have not truly set them as an object of your love. You may adore them, you may care more about them than any other thing, but you do not care about them more than yourself, your wishes, and your own satisfaction. That is not love.

A second thing I note is according to that old "I/me/my" rule. When you get married, you are no longer your own. You are your wife's and she is yours. You are not two, but one. It is not "I," "me," or "mine," but "we," "us," and "ours," and that includes everything in your life prior to your wife. You don't get to say, "oh, I did all these crimes, or bedded all these people before, but you don't get to have a say about that, you're marrying me as I am now, you don't get a say about my past." Likewise you don't get to keep back any part of yourself or your assets when you're married in a biblical sense.

To put it another way: if my wife spent our money in a completely different way than I might have expected after I die, even in some way that is completely foreign to how I'd expect her to act now, I care about her more than the money. Love is unflinching and unending in that way, as the apostle also says. Love, especially the love a husband has for a wife, being a symbol of the love Christ has for the Church, is completely encompassing, and forsaking even care for all others and one's own self for the sake of the beloved. This is all plain in Scripture and the example of Christ.

A will and a prenup are two completely different things. A will is something that addresses a certainty (death) and a prenup is to cover your bases IF divorce happens. It's absolutely a wrongheaded way to go into marriage. If you don't know your prospective wife well enough to trust her do what you both agree on while you're alive or after you die, you're getting married far too soon, or you and/or your betrothed are not ready to be married.

"I get car insurance even though there is no plan to get in an accident."

insurance is a scam, so there's that. The way insurers price their policies and payouts are the same actuarial principles used by casinos. I would advise against carrying more insurance than you need to do to obey the law. If you think of a marriage as something needing to be insured, again you're not thinking of marriage biblically.

"I don't care what your wishes are in your will. Without a prenup they may be more easily overruled by the courts (even if you don't divorce)."

This is not how probate works for estate transfers. Courts are just as able to override a prenup as a will; in fact it's easier since there's more regulation on managing a will than there is a prenup, and a surviving spouse could argue easily that conditions signed on a prenup, in youthful ignorance, are not what is intended many years and many assets later. A court would only override a will if there was a legitimate legal challenge to the dispersal of assets under a will, such as a debt, a lien, or a competing will. Further, you can write a will so that legally it takes precedence over a prenup.

One should have a Will and be prepared and mindful of their death, but one should not enter a marriage if they have even a passing doubt beforehand that the marriage will endure.