You lost me here. Mortgage interest deductions are one of the few areas that economists seem uniquely in agreement against. It tends to incentivize the wrong behavior (excessive housing size/mortgages and being a regressive tax that favors the wealthier propertied classes). Just because people like it, does not make it prudent policy.
In Canada mortgage interest is not tax deductible. What's done here is that, for your primary residence, any rise in value (capital gains) is not taxed when you sell it.
The US and Canada have roughly the same home ownership rates.
Prior to that, it wasn't uncommon for people in higher income tax states to exceed the standard deduction with SALT and mortgage interest.
The ability to save money and to be able to work your way out of economic instability is not a favor that government grants people. Upward economic mobility is one of the few things that held the social contract of taxation in place. Without upward financial mobility rules, taxation is simply a forced and pretty pohony "mob protection" fee.
The opposite is true. It inflates home prices (because it incentivizes larger mortgages) which ends up pricing out people from the housing market. It can also lead to increased defaults.
It doesn’t provide upward mobility. It’s simply a politically popular way to favor a specific class of voters.