You do make a good point.
I disagree.
What happened to Obi-Wan and Yoda:
- Jedi purge aided by Obi-Wan’s former apprentice now Darth Vader
- Galactic Empire takes over the galaxy
- Yoda and Obi-Wan face off against Sidious and Vader despite terrible odds
- Yoda fights Sidious to a stalemate and is forced to flee, as troops arrive
- Obi-Wan defeats Vader, leaving him for dead
- Obi-Wan and Yoda are now hunted by the Empire, branded traitors with the approval of the Senate, and are forced into hiding
- Obi-Wan and Yoda hide Luke and Leia
- It takes twenty years for the Rebel Alliance to become a significant threat to the Empire’s powerbase
- Leia asks Obi-Wan for help in their most desparate hour, Obi-Wan answers their call
What happened to Luke:
- Luke’s Jedi Academy is destroyed by his former apprentice partly caused by Luke’s unfortunate mistake
- New Republic controls most of the galaxy
- FO is growing in power, but at this point still a fringe government
- Despite the fact that there’s still plenty of opportunity to stop the FO with the help of the Resistance and the Republic fleet, Luke doesn’t even try, and goes into exile, leaving everything behind
- In Luke’s absence the FO grows in power to the point, that it is able to destroy the Republic capital and take over the galaxy
- Luke refuses to help even after his sister Leia through Rey informs him of their situation, and his best friend has been murdered