There is massive selection bias here. You are not showing how many homes were listed but didn't close. This is measuring only successes, not all the failures to sell.

Also you need to factor in realtor fees on both the original purchase and then subsequent sale (I do not know what they are in the UK, but in Canada they can 3%-7% of the transaction, and this exclude lawyer fees and mortgage discharge fees) which means that you need to get a certain percentage of "gain" in the selling price compared to the purchase price to make any real profit at all. If this was Canada, a good percentage of these so called "profitable sales" would actually be breakeven or slight losses.

Assume realtor fees of 5% on both the original purchase and the sale, this completely wipes out the profit of $168M on the $1.5B of sales. Hmm...

Strange article. It is like the author is not at all knowledgeable at all about how realestate works, or maybe UK is very different than Canada.