They most certainly do chase property investors who do claim incorrect primary residence. Remember primary place of residence is only while you live there so if you change it one month before selling it only offsets one month of profits and what if you have multiple properties you can't hide it all with that.

However the bigger problem remains that capital is taxed at half the rate of labour and this matched with tax free pensions has meant people with built up capital have gotten extraordinarily rich in the past decade and a half at the expense generally of the younger generation.