It is true that perihelion is not as close as it used to be and aphelion is not as far away as it used to be, but this has nothing to do with the precession cycle of 26,000 years.
This is yet another one of these cycles in astronomy that they don't bother to teach you about in pilot school - the ellipticity of the Earth's orbit round the Sun also varies over thousands of years. There is at present almost no difference in the heating effect of the Sun in January 4th (perihelion) or July 3rd (aphelion) because the difference in orbital radius is only about 4% and the change in declination is far more significant. But thousands of years ago, the change in radius was more significant, giving greater extremes of climate.