The above statement makes no sense. Neither OES_texture_float nore
OES_texture_half_float support linear filtering. Therefore, in the
absence of the newly proposed extensions you do not have linear
filtering. There is nothing to figure out.
We are already using linear filtering in limbo because we do not have these extensions. Adding OES_texture_half_float_linear but not OES_texture_float_linear makes no sense. Removing linear filtering will break a lot of peoples code. Not adding it will have the following effect:
It is inconsistent of its treatment of the already supported texture formats
It will force low-quality floating point textures on platforms perfectly able to use higher quality.