If you are ‘blading’ the skin on the face, won’t the hairs on the face grow back thicker?

No.  It is physiologically impossible for your vellous hairs (peach fuzz) to grow back thicker after shaving/blading.  Once the hair is cut at the surface, it has a blunt edge but this blunt edge does not mean that the hair structure itself has been physiologically altered.
Sometimes, waxing or threading can make the hair appear to be “thinner” but it is really not thinner at all.  Because waxing or threading treatments pull the hair from it’s root, the new hair grows with tapered smooth tip, making it feel softer.  But it is physiologically the same type of hair it was before.