In older versions, if user resize the graph page, or resize the layer in graph, the text label font size, the plot line and symbol thickness, the axis line thickness will rescale accordingly. This Scale Elements setting is a layer level property controlled on Size tab of Plot Details dialog. The default is Scale with Layer Frame.
For users who want to keep font size, etc. no matter how you resize page or layer, go to Preferences: System Variables dialog. Set SLF value as 1. (0 by default).
Workaround in older versions:
Choose Preferences: Theme Organizer…
On Graph tab, right click it and choose Set as System Theme to apply it for all new graphs in the future.
Note: User can also select Layer No Element Scaling theme and apply it to all existing graphs. And there is Graph: Fix Scale Factor… menu to set fixed factor for single graph.