I think if a name like malls.ca drops its not based on the industry. More likely its a case of a person owning a name he no longer needs and doesn't understand the value and is not aware there is an aftermarket he can sell it on, or a large business that doesn't want the hassle of selling it, or maybe the person passed away.
I know of one company that was marketing .com domains after the registrations expired, but they 'shared' just 10% of the proceeds and the procedure was a bit dubious given they only sold to the 'insiders' who made contracts with them. The other issue is they only used e-mail contact, and most people do not put passwords in their estate papers.
What we offered is based on non-payment - it could be any reason - of a renewal, in which case we renew on our own account for one year, and if the registrant does not re-establish contact, we get it after one year. It is not perfect, but it gives people 12 to 13 months to take care of things. We only had to invoke this two times, and once was for a .co.uk domain where the domain was re-registered for two years, instead of one, and the domain was settled after three years.
It would be better to have a system with some paperwork, just like a certificate of insurance, that someone can include with their papers which informs the family what needs to be done and what directions were given - manage, liquidate, sell on offer, and so on.