The concept, at least initially, of the Speed Force was less about explaining their powers as it was tying the speedsters together. Waid thought it was a bit ridiculous there was so many speedsters running around with different origins for their powers (aside from Wally/Barry), and he primarily created the Speed Force to link them together.
That's not to say writers haven't overdone it and used it as a crutch.
Because Barry is the Flash. When Williamson asked editorial about the previous Flash-Family, he was told they were off the table because that was always more of a Wally thing.And that concept hasn't been used very much in today's comics. We don't see much of those characters anymore.