Re: There can be no argument here . . .
An illogical premise . . .
Since measurements concerning size require spatial dimensions, your point is immediately lost. The Universe has never changed in size, per se, as the change is perceived to be one of volume. To imply differently is to state the Universe to now be spreading through non-Universal space, but anything not of this Universe simply does not exist -- therefore it cannot happen, as it cannot be.
But, yes, primordial galaxies were indeed different from the galaxies of today.
Cheers,
Dan