It's not that much more time, I learned Aikido in sequence alongside Judo and BJJ. Granted, I learned full time also, I had the advantage of my Sensei being a co-worker in my unit in the military and my superiors were very pro martial arts, I spent 4 to 8 hours a day learning stuff for years. Aikido principles and concepts can be taught through a fe different exercises and while learning the techniques, I tend to teach one or two techniques per session, one technique per hour so there is plenty of time for practical application and for everyone to have the technique applied/apply the technique on everyone else. You could pick up enough Aikido to improve your BJJ or whatever in a few weeks, even if you only did a few hours a week. Mastery is a long road but the movement and principles of Aikido are in my opinion the core of the art. I can make a Muay Thai vertical knee or an elbow strike into an "Aikido" move by directing/redirecting my force and momentum with the force and momentum of the opponent. Thats why I believe the theory is the real treasure.
Also, while it lacks pressure testing, I have rarely seen a "varied" use of force taught anywhere else, most fighting is full force or nothing, but Aikido teaches superior control and a tempered response. My original teacher would take people out to a field or parking lot and encourage them to hit him and then he would spend however long just slapping their hands away, tripping them, dancing out of their reach and otherwise just playing around until they got tired and gave up as a way of teaching what Aikido "is" to new students or other martial artists. Nothing is more dejecting than trying your darndest to punch and kick someone and having them laugh at you, wipe brow sweat on your shirt and otherwise tease you while they simply bat away your best strikes. That is the ultimate goal though, a well disciplined fighter who can apply just enough force or no force at such a high level of competence that they win the altercation and maintain control of the situation in a way that protects both combatants, the same way you keep a kid brother or young son from hitting you while they rough house but you also keep them from getting hurt also.