[shimms]

There is a huge difference - the duty to mitigate losses.

A landlord can re-let the space to another tenant, and start earning revenue again.

The money loaned however is gone until it is repaid. The total loss of a loan is the principal remaining unpaid at time of default, since you have permanently parted ways with the money once you transfer the funds to the borrower.

A lease on the other-hand hasn't deprived you of anything. You've still got the asset that can be released.

The losses in this instance are limited to the period of time the premised was vacant and unpaid for, as well as associated other costs such as an amount of any incentives provided as a proportionate to the length of the lease term remaining, legal costs, reletting costs, advertising and renovation costs etc.

You can't simply sue them for the entire value of the lease - especially if someone else moves into it and starts paying rent, you'd be double dipping.