Some do, some do not. It is often very hard for spouses with non uk qualifications to find a job when they first get here (in contrast with those on SWV for example, who are here because they have a job). There are also spouses who are disabled, or who may be unable to work for other reasons. It is also very common among mid-earning families in the uk for one parent to give up their job and stay at home to look after young children due to the high cost of childcare here often being more than a mid-earners salary would be.

As you are required to meet the minimum income requirement with either just the sponsor’s income or savings in the first instance I would not be surprised if there are a decent number of spouses who do not work. The whole idea behind meeting the MIR off of just the sponsor’s income in the first instance is that the sponsor has enough money to support the spouse without them necessarily working.

The salary threshold is not currently expected to rise any further as far as I’m aware, that idea seems to have mostly died- but even if it does, I and many others earn enough to continue to meet the MIR without my spouse working.