While releasing on all carriers would be amazing, people keep saying that and yet it also doesn't matter. When People think Android, it usually is Galaxy before anything else and the same with Windows Phone and Lumia.
Lumia presently is the face of WIndows Phone(Which makes it all the more reason it is stupid that Microsoft is delaying any major lumia releases in favor of this phone).
Even with HTC M8 being released on all carriers for Android, it is a flagship nonetheless for HTC but it still has yet to achieve any major success really(i mean it has but not really)
If we are to go by the top5
http://www.androidcentral.com/samsungs-smartphone-market-share-takes-nosedive-q2-2014
HTC is nowhere to be found in the top 5(neither is nokia but that's apparent) despite them always releasing their phones on every carrier, So i am not sure why people gripe about the Lumias not being released on all Carriers at the same time.
Yes it could sell more...OR it could sell the same amount it does now just spread across more carriers. You never know.
it sounds better to say that At&t sold 1 million Lumia 920 vs 330K for Att 270K for Verizon, 250K for Sprint and 150K t-mobile
So yeah it'll be awesome to release on all carriers at once(So people can stop whining about this phone not releasing and how that somehow spells bad for Nokia lmao) but it is not indicative to continued success.
Let's not forget...the HTC M8 is on all carriers and also still isn't the preferred handset(Samsung, Sony, LG and MAYBE motorola have it beat. Let's not also forget that Blackberry is also available(or was) on All/most carriers and that didn't do anything to increase its success,
Also let's not forget, speaking of Galaxy, Samsung actually had a similar track record with their Galaxy Series. The first & second generations were variants. At&T got the Captivate, T-mobile got the Vibrant, Samsung got the epic and Verizon got the fascinate.
(At&t got the 920, T-mo got the 925 which later also went to At&t and Verizon got the 928...Sprint got nothing sadly).
Then 2nd Gen Galaxies got even more crazier with their variants and releasing multiple variants for various countries(just like 2nd Gen Windows phones). Lots of models were exclusive to one carrier.
It wasn't until Gen 3 with the Galaxy S3 and late S4 and S5 that Samsung begin doing global releases WITHOUT variants.
So yeah if anything, Nokia is on a similar path with Windows Phone just like Samsung is with Android hence my opinion it is the Galaxy of WP.
For HTC to be considered Galaxy of anything It first needs to
1. Manage to outsell the Leader...which it has proven unable to do so far on WP and Android
2. Become the Mascot/Face of the OS....Didn't the 8x have the "Signature" tittle with it. Little good that did and those phones actually looked better than the 920. People simply just didn't want it lol
3. Become the De Facto Standard
Samsung and Nokia both do that on that their respective platforms....and if Samsung ever manages to be of some use to the platform, it is completely game over for HTC and a threat to Lumia as well