I just checked. So far bank still allow 50% debt to income ratio

for good credit applicants.

Of course they can change it any time. But that does not mean they will likely do it.

Bank needs to make money. They have to pay for their employees, they have to pay for their buildings, they have to pay CD interest to their customers. They cannot stop lending money. The business will continue.

They may be more careful and more selective. But no need to panic. Mortgage market will not disappear.