As someone who used to service both a Race Drivin and a Daytona USA (among other racing cab) I can tell you that power wise the Daytona FFB motor is every bit as powerful and accurate as the one used by Race Drivin (arguably more so, in-fact)... Whether or not Sega actually leverages that accuracy in their game codes is a question for another discussion but I would argue that every Daytona unit you've played was either broken or had the intensity turned way down... which is surprising as the Race Drivin FFB was far more prone to failure than the system used by Sega.
Ive serviced both Daytona Usa, Hard / Race Drivin sitdown, seen the tiny motors in Rush, and serviced a lot of other drivers / mechs that are similar.
While Daytona USA (orig), was one of my fav. racers.. Its FFB wasnt even close to the power output of the Race Drivin setup. Maybe half that power max.
Its not just the motor strength.. as RD is directly effected.. where as DT is a belt slip, as far as memory serves me. This means that a lot of the power is simply wasted and lost.
Also, Daytona's wheel.. or for that matter, I do not think any of the typical wheels out there, can 'Drive themselves' with the level of accuracy that the Race Drivin wheel could. For example, RD could stop at some odd angle, like 30 degrees.. and holding itself there. No user interaction needed.
As for serviceability... I didnt have to service the FFB on DT, only the pots and wretched gear shifter that ATE switches constantly. With RD, I never had to touch the wheel in the arcade, in the 3yrs I was there. I replaced the pots on the gas & shifter once. Most of that games problems were board issues. I repaired it less than the Daytona actually. But that cant be said for another location, where the boards were flaking out.
I did finally run into a RD wheel that needed some work. The guy left the auto-drive attract mode on all the time.. and the brushes wore out. He had a new set made, I cleaned the motor via the open / shut access ports, and installed them. Rock solid ever since. And besides the gear shift pots going once every 6yrs? ... never had to touch that either. On DT, I was in the shifter once or twice a month changing bad switches out.
If you really have never felt full force on RD, clean the motor of the carbon dust, then crank it to full power in the service menu. You will be in for a real shock. The motor is like a 9" diameter beast.. something you might see inside of an industrial machine, washing machine..etc. As for connectivity... a simple shaft connection is easy to do, even with full-through motors. Its pretty much like what you see with a buffer that has two ends. A simply coupler is easy enough to do the job.
As for why they dont make them like that anymore... its due to costs. As times progressed, they started cutting every corner they could. Eventually, a lot of MFG. decided to use Happ's generic controls, rather than design, machine and test all customized mechanisms. Sad indeed.