Technically the comparison is not totally fair, that Hubble image was taken in visible light, while Webb's in infrared. Dust blocks visible light stronger, so background stars are effectively hidden from Hubble, but not from Webb. Here [1] you can see same field in visible and close infrared taken by Hubble. Webb of course shines in all the fine details and faint stars number.
[1] https://cdn.spacetelescope.org/archives/images/screen/heic15...