I'm sure it's been noted before but I find it baffling as to how difficult it is to get the egg yet it only provides a 10% boost. As a person who is generally busy nowadays I resorted to the egg to help speed up the lvl up Grind due to limited gameplay time (which ofc would benefits others too). Now this change was dated back in 2017 I think or even earlier (please correct me if I'm wrong, didn't research much into when the change happened) and yknow, sure has been a long time...
However if the 50% exp boost not possible (or at least 25%) I have a suggestion:
I believe the lucky egg should have more of a chance vibe to it. After defeating a wild pokemon/trainers etc, I think the increase xp should be either:
20% chance for 10% xp boost
20% chance for 20% xp boost
20% chance for 30% xp boost
20% chance for 40% xp boost
20% chance for 50% xp boost
So overall if you are very "lucky", you can get max egg xp boost. And I think the ratios should be equal imo but eh what do you guys think?