Which one will sell more than the other? 2.0

Lionel hands down but with MTH and Atlas back in force, and Menard's filling the low end. All will be cutting into Lionel's sales.

As for hijacking, I don't mind, by the time a thread gets two or three pages in, it's so off the rails it's not even close to what the author who started intended.

In terms of number of items sold, Menards should be the clear winner unless that cannot provide adequate quantities.

As the stigma of MTH's confusing non sale sale wears off I believe they will gain ground on Lionel but only up to a point unless they are able to generate new tooling.

Lionel is still the big gorilla if for no other reason than their penchant for eye candy new items/paint schemes and upscale set and Ala carte offerings.

Atlas is trying to up their game unfortunately they are the company I am least familiar with. But I will say the Strates Carnival Train would be top of my list for purchase from them.

Best wishes to them all

As usual I am inclined to agree with Joe but Menards is only in my sights for certain products - not including engines. I already have more Menards structures than I have space to deal with properly but I keep looking at what they make. 

My reservation about all of the 3rail O scale manufacturers/importers mentioned above (excluding 3rd Rail/GGD) is their inability to deliver quality, reliable products. I don't see that changing any time soon so no Lionel/MTH or even Atlas catalog is going to tempt me except in extreme circumstances.

As to new original items and cost factors for both new and seasoned Modelers, can't deny Menards impact on the Hobby.
MTH, if they had only known how many of the dies they sold and the dies left to continually come up different with both real and fantasy schemes has a limitation. Unless they are going to try and produce a new never before item.
Atlas is a hit or miss on "O", can't tell if the really want to join the pack again. I have several engines 5 to 10 years old that never gave me a problem. Their rolling stock, boxcars, tankers, etc. are superb.
My opinion, Lionel is big on big engines and BTO, (that's were the money is for them). 2 factors that keep me from purchasing, yes, the price and I don't have the space for 6 to 10 large engines taking up valuable railspace and I'm not a collector. Everything I have, 16 engines and rolling stock except for some boxcars and hopper cars, are on the layout.

Well, I have items from all of the candidates on or running on my layouts, but if you are limiting the inquiry to new rolling stock purchases, my personal answer is "none of the above".

First, my main focus is on PW Marx (recently expanded somewhat by my recent acquisitions of a pre-war tinplate Marx M-10005 streamliner, and a Williams GG-1), so I have no interest in new catalog stuff, QC/price issues or not.

OTOH, I have plenty of (mostly aftermarket) layout pieces by just about all the mentioned companies already, and I'd throw in WS (like others, I'm scratching my head trying to figure out where I could put their newly-announced vintage motor court, once it's available!) as a company regularly producing candidates for some of my modest monthly Social Security income!