5 is fine for Drai, I honestly don't care about the length at all, I care about the cap hit. I'd be fine with cheaper 1 year deals really, although that obviously wouldn't be ideal. Anything 3+ is perfectly fine and allows the mgmt team to make the decisions about the future they need to, and shows other players in the league that he is serious about staying. The cap hit is where the rubber hits the road.
A 5 year deal is great for the Oilers, I just don't see why Draisaitl does it.
Stamkos just this month got a 4 year deal at $8M at age 34, and Stamkos isn't as good as Drai at the same ages. He will 100% get more than $8M at age 34, especially with the cap rising.
Your overall point about whether somebody would pay him $13.5M is valid though, as that is certainly an unknown. I suppose it could happen, but it would require Drai not falling off at all, or the cap rising quite a bit in the next 5 years.
Thats fair, I don't know what Draisaitl will get at 34/35. I just know it won't be close to 13.5M. Maybe another team overpays and gives him 10M with the cap going up. So instead, he's sacrificing $10M total. I don't know why he wouldn't just sign a long term contract and then ask for a trade in the final years if the Oilers aren't competitive. It's not he's signing a 5 year deal in the hopes of getting paid more than he's currently making.