Not going to name any company's that claim that it does as that isn't hard to find out by reading but I have to study every bit of the spec's on scopes for a living so I can advise people. I try to keep my business life separate from my online life so I will leave it at that. :-)
The reason that a lot of company's are going to the larger tube is so they can get more elevation in them as Long Range Shooters are demanding it and demand is what drives the market or we would still be using mostly 1" scopes.
Two things will improve light transference. One is the size of the objective bell and the lenses in that area has the major part in light transference.
The next part that contributes to light transference is the lenses coatings and whether their coated inside and out or just one side. This is also a lot/some of the difference between cheaper scopes and higher priced scopes.
Also some eyes as they get older (mine
) cannot see more light than some of the smaller objective bells can give you. I have a hard time telling the difference between a 50 and a 56MM and always figured it was imagined as without knowing which is which I cannot tell.
Now all that said a 1" can be just as bright as a 30 or even a 34MM tube depending on the size of the bell and coatings. OH and the quality of the scopes glass too.
Another thing I see that really blows my mind is some scope company's really blow their numbers on light transference way over what it actually is. Sit down sometime and start reading the actual spec's on a scope. Once you understand them it will start to open your eyes a bit so to speak.