Actually
its not going to remain the same. It wont be double either. It will be slightly less than double but the *odds* of it happening do go up. Because you increase your exposure by using two drives. I saw a study a while back, maybe it was on Backblaze I dont remember where, that compared raid0 to raid5 for data loss odds per year. Raid0 had a 2.6 and raid5 had a 1.6 I think.
You are comparing having 1 drive vs 2 drive in raid 0 yes
But if you are comparing having 2 drives vs 2 drives in raid 0 making the only difference raid itself then no. you still have " 2chances to fail" raid or not.
Scenary A: 2x 4tb drive no RAID
Drive1 fails: You lose 4 TB of data
Drive2 fails: You lose 4TB of data
Both fails: You lose 8TB of data
None fails: You loose 0TB of data
Scenary B: 2x 4tb in RAID 0
Drive1 fails: You lose 8 TB of data
Drive2 fails: You lose 8TB of data
Both fails: You lose 8TB of data
None fails: You loose 0TB of data
You can play around with the probability for the drives to fail by they remaining the same between A and B (When not looking into drive usage pattern)
But trying to bring hate on raid 0 by bringing in faults that has nothing to do with the RAID itself (aka 2 drives) is just biasing your results with another factor. ( Now that factor might be important to include in risk assessments based on the situation but it's not due to RAID)