If they don't it increases the chance you will not see the higher end benchmark scores due to thermal limitations,and you also need to consider most tablets have 10.1" screens and under in size not nearly 13" screens like the pre-production Core M tablet.
Their Llama Mountain reference tablet comes in two sizes, 12.5'' and 10''. Not only Core M fits a smaller tablet but it's also thinner and lighter.
The 12.5 inch tablet measures 0.28 inches(7.2mm) thick and weighs 1.48 pounds (670 grams) while the 10 inch model is even smaller, at 0.27 inches (6.8mm) thick and 1.2 pounds (550 grams).
There are rumours that Apple will introduce a 12'' iPad, and other Android/Windows vendors are interested in larger tablets as well. Those should more expensive their 10'' counterparts, so Core M could be a viable option. 10'' and smaller tablets are usually cheaper (up to $500), that's Bay Trail/Cherry Trail territory, I'm not sure lots of customers would be willing to pay $600-800 for a faster iPad sized tablet, targeting larger tablets/convertibles makes sense.