This is wrong. The reason rent is going up is because there's more demand than supply. Reducing the amount of money everyone has by a constant factor (in this case 3/5) will not change the supply/demand imbalance, so it won't solve the problem. Put another way: the reason rent is so high is to prevent some people from being able to purchase the product. There's not enough of it to go around. You're basically blaming the best known system for allocating scarce goods for the fact that scarce goods exist.
If you look at countries that try to act on the above notion, you'll find that high prices are replaced with impossibly long lines. And shortages. This is because reducing the price will only increase the demand for that good.
A better world view would be: if the baby boomers hadn't all had kids at the same time, we wouldn't be experiencing housing shortages. This theory (though incomplete) at least puts demand increases front and center. You could also blame cities for not allowing/supporting the construction of new housing. That theory (though incomplete) at least puts the supply shortages front and center.