wait, what? There's a $250k capital gains exemption for sale of primary home lived in 2 of past 5 years, so isn't capital gain basically irrelevant to anyone but very wealthy? Do you know something I don't? (reasonably likely)

What he means is that the deduction has been "priced in" to the price of homes/mortgages. In a similar story, a company I used to work for once offered employees a $x incentive to live close to the office. They then found that the price of homes in the area immediately went up by $x.

Got it, of course! Capitalized could be a formal tax term in this case, but it was just meant in terms of actual plain capitalization generally.

Yeah, mortgage tax deduction, like all incentives that encourage borrowing more money, ends up being a transfer of wealth from new homebuyers to whoever had owned property outright (whether older long-term homeowners or developers or real estate investors).

Very important point.