Couldn’t disagree with you more on everything you say. I give a full explanation here, but will summarize below why I disagree with your 5 points.

“Reason 1: Your home is the most important equity you have”

This is not relevant. In fact, if you’re really concerned about the risk of losing your home, you should invest extra cash to build a larger portfolio. Then, if you lose your job, you can use that portfolio to continue making payments and avoid losing your home.

“Reason 2: Your mortgage is the best “risk-free” return around”

Possibly so, but few people are in a situation where risk-free investments will enable financial independence. By taking on moderate risk, you can dramatically reduce how much money you need to set aside each month.

“Reason 3: Do you really trust governments? Really?”

Another irrelevant point. I trust the government to behave as it usually does — somewhat ineptly, driven by personal political calculations on the part of elected officials, and solving problems only when forced into it. This has zero impact on whether you should prepay your mortgage principal. If you invest rather than throw extra money at your mortgage you will be able to pay off the mortgage in full earlier, since you will (on average) get annual inflation-adjusted returns in the 6% — 7% range in the stock market, rather than about 1.1% (which is what you pay on a 4% nominal interest rate after adjusting for the long-term 2.9% average inflation).

“Reason 4: Your home can be your piggy bank of last resort”

See above response.

“Reason 5: Home values can drop very quickly”

This is true, but also irrelevant. As long as you keep making mortgage payments, a drop in home values doesn’t affect you in the least, unless you want to sell, which is a whole ‘nother issue. However, even then, getting a 6%-7% annual inflation-adjusted return will let you pay off your mortgage much more quickly than making extra payments against principal rather than investing.

Beyond all the above, if you can deduct your mortgage interest, that’s another reason to not prepay your mortgage.