First, the "straightness" of the fork does not affect the trail; You can have two forks with the same geometry, i.e., position of the front axle with respect to the steering axis, but one with curved blades, and one with straight blades (angled forward from steering axis). Regarding stiffness between those two forks, the construction of the fork blades has equal or more effect than the straightness of the blades.

Second, you may have it backwards; Rewind to the early 1970s; General Motors wanted to have their second generation Chevy Monte Carlo have good tracking at freeway speeds, meaning, a positive centering force. They looked at Mercedes cars which had this, and had more caster angle (resulting in greater trail), so they imitated that and designed the Monte with the same caster angle. As my father would say, "A little knowledge is a dangerous thing." Yeah, Benzes had a lot of caster, but the wheels, tires, and steering linkages were all relatively light. The Monte had typically USA overdesigned-heavy on all of the above, to prevent warranty issues (only in recent decades has GM gotten away from that, instead, designing things light, test like heck until breakage, then beef up only where it broke, test again). So, the Monte pre-production samples go through testing... problems; That greater trail does provide greater steering centering, but the greater mass in the system makes it overshoot, greater with each oscillation ("positive feedback"), to the point that it goes out of control. In other words, SPEED WOBBLE. To fix this without a costly redesign, which would also delay vehicle introduction, they fit a "steering damper", basically a horizontally-mounted shock absorber with compression and rebound settings the same, to damp out (actually prevent) the oscillation.

So... increasing the trail, car or bike, will improve low speed stability and centering, meaning more likely to be able to ride the bike no-handed, and steering need less attention on long rides, versus twitchier, more agile handling, like for crit races. But at high speed, that increased trail and higher centering force at speed, can overshoot and cause oscillation.

Also, from what I have seen on this, I think the torsional stiffness of the frame, and lateral stiffness of the fork blades, may both be critical; My '89 Cannondale crit racer was the stiffest frame they ever made I think, never a hint of wobble as I maxed out the speedo at 65 kph. And relatively steep angles, 74 degree steering axis and short trail I think. IIRC, as they, and others started to go smaller and flatter and very thin wall on the top tube (less torsional and bending stiffness), for both lightness and perhaps smoother ride, I think some had speed wobble, until they reversed that trend a bit. I would hope that no new bike, especially a road racer, would go to production without testing for speed wobble.

EDIT: a bunch of good info on wiki, confirming what I said, plus other factors, especially under "two-wheel vehicles", but I recommend reading it all:

https://en.wikipedia.org/wiki/Speed_wobble