If the #2 requested feature isn't needed to sell consoles they why bother adding any other features ever? After all since they won't affect sales, then why waste any time on adding feature requests #3, #4, #5, etc...
That's a ludicrous argument. Firstly, BC isn't the 2nd most requested feature - it was the second most requested feature for an update of an existing console. There are for more important features such as price, performance, games library, services, etc. Secondly, adding features to any project is always about cost/benefit. Sure, BC is wanted, but the cost to include it in consoles is very high. Balanced against benefit, the cost is too high so it's not included.
Besides as you others like to always point out, the first few months sales don't mean anything for the long term prospects. So just because they sold millions for the first few months doesn't mean that not having bc isn't damaging their long term prospects.
Huh? BC become less important as time goes on and the consoles have new libraries. One need only look at XB360 for that. Halo was refactored for BC to help the transition, but then MS gave up on adding more BC titles because no-one cared after that.
The evidence is completely one-sided.
1) Last gen, the console version with BC was far less desirable than the version without BC
2) This gen with no BC is the fastest growing generation of any
3) There has existed a platform offering full BC for over 10 years (PC), yet core gamers prefer to play on consoles without BC. If BC was that important, these gamers would choose PC over console. Instead they choose consoles which prioritises cost, convenience, peer pressure, or whatever far more important aspect than BC
4) Gamers who switch platform lose compatible, but they still switch (~50 million PS2 owners swapped to XB360 going by numbers)
5) Wii U is fully BC going back multiple generations but is selling like a dog, while Wii U owners are asking for new games
6) Sony invested in BC research but eventually gave up
7) Sony and MS, who clearly would have access to amazing stats and their own research, felt they were better off with clean-slate designs losing BC
8) Even among your beloved mobile example, people jump platform losing access to all their content without any problems. The core services, FB and Twitter etc, are available cross platform, and the content they do lose is stuff they don't care for. So customers who own an iPhone buy an Android, and
vice versa, and don't give two hoots about the loss of massive amounts of their old, used library.
There is one mind-numbingly obvious, indisputable conclusion - that gamers like BC but prioritise it quite low in respect to purchasing decisions. Given the considerable costs in implementing it, it is avoided as a feature, but if the costs can be brought down (eg. HW synergy next-gen, if there is one), it can be considered as a value-add feature and may be included. BC is thus not unlike every other console feature considered in design. Set your design targets and priorities for features like cost, ease of development, performance target, aesthetic, BC, services, and then create a product that best balances them, making sacrifices in some areas to support others.