Idk, because it’s a joke and I’m not really that invested in the specifics of the latest ad garbage a tech company is pushing? Ads expand to fill all available space. If it can eventually become a video ad, it will. Just give it time. These things never go in the other direction.
…Except you knew it was sarcasm. Hence why you made your comment in the first place. Unless you thought I was earnestly praising Google for making new ads?