Nobody is born perfectly capable of playing DF, there is the possibility that players will refund the product through steam soon after a frustrating 20 - 30 minute experience, without ever knowing about the free DF classic version or the differences between them for a 'dry run' of the game. A link to the classic version should be properly signposted somewhere on the steam-page.
That's the kind of noob games developed by large committees end up catering too. In that respect, yes, time would be better off not being spent on trying to please those people.
Its worth keeping in mind the existance of chronic idiots is a known phenomenon (I've met one or two in my real experience within my lifetime), set apart from players who are fresh and inexperienced but have the capacity and patience to learn, or those who might percieve the gameplay through the lens of a disability like ADHD or epilepsy (given there are some alternating flashing things); there will be plenty of challenges to make it accessible.
If you want a case study of target audiences being foolhardy to the extreme, the Family Guy MMO lives in infamy for having the most incompetent user-base which lead to its imminent commercial failure (the show itself was unaffected) and the creator Seth MacFarlane briefly falling into depression because a large majority of players couldn't go through a door to end the tutorial (this was a bit earlier on the internet than most) for no technical fault on the developers side, they were just totally perplexed that their target audience were probably really young, lacked the intuition and mostly ran around the tutorial hub shouting show-quotes with their characters.
In a similar vein, while i hold the opinion that DF premium players are highly unlikely to be that difficult, any sort of tutorial should be revistable and well talked through either ingame or outside it through community help.
That might be true if "readability" were universal. What's unreadable to some is perfectly reasonable to others.
This is the other distinction which actually much of the DF community has been jostled about across time, reading ascii is a learned skill and the purpose of developing 3rd party applications like the LNP preloaded with graphics took into account already get around most new player problems, the steam version takes that to a new dimension.