It could also be considered unfair to ask other factories to compete at the same level as only Honda and Yamaha can with that biased rules package. That rules package favored those factories who already have a competitive, refined package. 5 engines, 20L - Honda and Yamaha didn't get there all at once either. It took a few years, with those numbers arrived at by slow degrees. 24L to 22L to 21L to 20L. These rules favor the factories with the largest budgets and most engineers.
What's good for the class is more bikes capable of being competitive. For the last few years we've all known full well the only rider would would win a race, let alone a championship, was on one of four bikes. Those bikes rarely change hands. 1 Honda has had the same rider for 10 years. This is JLo's 8th season on a factory bike. Barring 2 years at Ducati, the other Yamaha has been Rossi's since 2004. The "championship" seat at Honda has only been held by Hayden, Dovi, Stoner and Marquez over the past 10 years. Young talent has nowhere to go to truly compete for wins and a championship. The increasingly strict rules have kept other manufacturers out because it simply costs too much to complete at that level.
The rules were written that way due to Honda influence because it gives them a technical edge - they are the ones best positioned, with the most money and engineering talent, to succeed under those restrictions. Yamaha is very close as well. What we see now is an attempt to reverse the rules package to get more players in the game.