When I consider Nintendo, Sony, and Microsoft (for console development only), their sales are primarily dependent on what games are available, product capabilities, and product details (price, longevity, etc.). The console market is so interesting because they have to fight on multiple fronts.
For the sake of relevant discussion, let us consider Nintendo. Nintendo has to please game developers and consumers simultaneously to have a successful launch. While they are marketing their console, developers want to help in a way because a new console is a new opportunity to have a different segment in the market (especially with Nintendo). If the developer reaches new exposure, revenue will increase and of course would mean greater profit.
So when the Switch reaches high praise from multiple developers, I'd argue there is a level of genuine interest. If they had any doubt they couldn't make money from this console, they would not develop for it. Plain and simple.
However, they also need to boast on with how great the system will be so that the user base will be as large as possible. Once again, a larger install base, more opportunity to sell their games.
The invisible hand will lift consumers as developers 'market' their own dedication and resources to the new system. Consumers, more specifically gamers, have their favorite games from their favorite developers. If a developer reaches to the right gamer, he will be happy with the product Nintendo is selling. Which also means any first party developed games will be reaching to the greater audience and have more opportunity to sell their software, in addition to the hardware of course.
Now, if Nintendo doesn't please the gamers, developers would either opt to praise it in hopes to sway the consumer or to ignore the product to not be badly burned by the lack of sales.
In the Switch's situation, developers appear to be relatively pleased with the system itself – this also indicates that there is potential for the install base to be rather large (or large enough) to profit off of. As a result, more gamers are likely to pick up the hardware because developers are continuing to make software for it. Makes sense, right?
The WiiU had much support – developers know Nintendo's history and brand image. In addition, the WiiU is a successor to one of the most successful consoles in history. Of course developers think that this is going to be an awesome opportunity to make big money.
However, Nintendo failed its marketing and the system flopped. Hardware itself was rather decent, but no one was buying the system due to much confusion. As a result of that, developers began to pull out realizing that their resources are best spent elsewhere – ESPECIALLY since the WiiU was known to be hard to develop for. Therefore, it was a spiral staircase going down for the WiiU as it wasn't retaining developer support, which upset the gamers and had awful marketing, which confused gamers (more so the casual buyers) and fudged the developers opportunity to profit.
My point is, the console market is very interesting. Right now, Switch is doing okay. Marketing has been pretty spot on. And, once again, if developers didn't think it would do well, they would pull out immediately. It is an effort on both fronts – Nintendo and the developer – to make a console successful.
TLDR; developers only care about money and will only dedicate time and resources if there is an opportunity. WiiU failed at getting a big user base, yet developers are showing confidence in this new system.
I have some marketing experience as a freelancer, so this is just my take and perspective from what I know. I'd love to hear what you guys think about the Switch and the console industry in general. It truly is a very fun market to analyze.