I get your frustration but the reality is that it's not Earth's fault. It's about how exalts are weighted regarding flight size - something that Earth has no control over. Additionally, Earth has NOT been pushing for three months, outside of two pushes. Any place in Dominance is from individuals exalting (for personal profit) and NOT a push from the dominance teams.
This year Earth has had one Profit Push (February 9th-15th), one planned Conquest (April 13th-19th) and one unplanned Conquest (January 5th-11th, which had them in competition with Light who also weren't planning Conquest initially), whereas Arcane have done three Profit Pushes (one is currently ongoing!) and one Conquest.
To be clear, a Profit Push is not about ranking on Dominance - it's about making money. If we look at the dominance rankings for Arcane's profit pushes this year we'll see:
January 12th-18th: Arcane comes 3rd place, losing out to Fire (1st) and Earth (2nd).
February 16th-22nd: Arcane comes 4th place, losing out to Shadow (Festival Push), Earth and Ice. (1st, 2nd and 3rd).
April 27th-May 3rd: Arcane is currently looking to be in 5th place, behind Light, Earth, Fire and Ice. (1st, 2nd, 3rd and 4th).
However, if we look at March 23rd-29th which was their most recent Conquest push (which is about ranking on Dominance), they came first. 2nd and 3rd place were Earth and Fire respectively. When Arcane as a team want to conquer, they conquer.
Again, to be clear: Arcane have only aimed for the top spot once this year (so far). Last year, they did it twice (one Conquest, one Festival push). In 2023, it was the same - they lost their Conquest in week 48 because they were in competition with Light. Every other time? They've taken top spot in Dominance.
This goes for the other teams as well - their Conquests often succeed, outside of when two flights are actively competing for Dominance. This is not an issue of Earth constantly pushing or "letting" other Flights win. This is just how team size, exalt weights and Dominance/Pushes work.