Taking the notion from HIPS as an example where it is noted that some koryu found and applied ways in which to combine IT into martial training as a whole entity, it can be done.
The question is, who does so nowadays and does so with succes?
But how did the koryu do it? Did they first teach techniques and later filled them in with IP? Much like Takeda taught some/most/all people jujutsu first and the internal stuff later? Do we want to do the same in aikido? Or do we want to have new students practice some basic exercises first for a few years (so no actual 'aikido') and only when they have a sufficiently developed body, start doing the aikido techniques?