I've had a similar thought before.
But what I have come to realise is people often misunderstand the inferior as automatically being unconscious to the fullest extent. The inferior is actually more or less conscious/unconscious to the degree that an individual attempts to accept it's influence and pitfalls on their own life and then engage with it in an aware manner.
Also it is not that a person is incapable of appropriating their inferior function in terms of application, it is more that it causes a degree of discomfort and stress when they attempt to engage with the mindset behind it.
For example, an IFP can use Te to apply to certain elements in day to day life, algebra, taking notes, perhaps organising their work space or approach to work somehow. Now it is debatable that these are activities to be associated with Te or any particular function at all.
But that's besides the point, which is that an IFP in this example can use Te to their hearts content, but what they will always struggle with is the mindset behind Te.
They cannot willfully disregard personal valuations in favour of impersonal objective criteria, as this involves unbalancing the cognition they have spent their entire lives with. However this does not stop an IFP or any other type for that matter, from learning to understand those infamous 'inferior outbursts' and perhaps that sometimes the facts do speak for themselves.
Another example would be INJ's. INJ's can engage with Se by dancing, practicing physical activities or even drinking....in other words enjoying the experiences of the senses and the adventure that can bring in the physical world. What they struggle to do is maintain that response ready mindset that is native to Se.
Their minds are always looking for that trigger to space out and pull in all those Ni frameworks. Attempting to hold the attention here and now with a natural cognition like that, would be like trying to clean an oil spill with a flamethrower; eventually it's going to clash and combust.
In any case the most important goal as I see it, is to attempt to understand the inferior in terms of it's influence on ones self. Using the aforementioned examples we could see how an IFP attempting this might be more inclined to organise their life and make use of the surrounding systems to do so.
And for an INJ this might include not planning as much or at least attempting to predict the outcome as much, letting oneself relax once in a while and enjoying moments as they arise once in a while, so as to avoid becoming a neurotic who misses out on some of the simpler pleasures in life.
None of this comes easily though, an individual must push themselves to develop this acceptance and awareness of the inferior.
But then many of those things in life that are worth having never come easily.