I know you're on the AD bandwagon since last yr so we'll agree to disagree.
Dovi won an equal number of races as Marquez, the champion last yr. Every MotoGP Season preview this yr said the title race would be between Marquez and Dovi. So no, he still isn't the underdog by the very definition above. That title would go to Zohann Zarco for 2018.
Dovi couldnt pass Lorenzo in Jerez, and (uncharacteristically for him) outbraked himself in a desperate passing attempt, which started the chain reaction to the accident. Dovi had every responsibility to pass cleanly as Lorenzo did to get back to the racing line cleanly. Again we'll disagree on this.
Crashing out of a race 2 corners after taking the lead is crumbling, End of.
This is interesting, so you're going to double down. Ok, let's explore this another way.
Who is the 'underdog'? Check one.
(Poll open to anybody, not just you.)
Rider: UNDERDOG
1. □ Marquez □ Dovi
Manufacturer: UNDERDOG
2. □ Honda. □ Ducati
Let's ask this a different way. Who is the championship favorite, that is the opposite of underdog?
Rider: CHAMP FAVORITE (who is NOT the underdog).
1. □ Marquez □ Dovi
Manufacturer: CHAMP FAVORITE
2. □ Honda. □ Ducati
We could end the discussion here, but let's elaborate.
You want to 'hang your hat' on Marc and Honda as the 'underdogs'? Otherwise Dovi/Ducati are the underdog! Yet you want to argue the guy who has won 4 of the last 5 championships, and the manufacturer that has 4 different individual champions since 2000 are/is the underdog? In that time, Ducati have scored a solitary championship with one of the all time fastest riders, one compared to guess who... Marc Marquez. That's your underdog. Wait, you'll say "point out where I said Marc/Honda are the underdog."
Let's examine the notion of "crumbling" now. Marc Marquez had 27 crashes and won the title, kinda puts your notion of "crumbling" in perspective. I'd agree with you if it were under the circumstance of a title deciding moment, but we're talking about the 5th round of 19. Dovi has had 1 crash at a venue that saw a shitload of crashes, including Zarco in the lead. By your standard, Marc crashed at Mugello, his championship has "crumbled"?
Recap:
1. The 2018 Underdog: Marc Marquez (right?) No, Dovizioso=underdog.
2. Crashing=crumbling, see Marc Marquez.
Most people assert (your words below) that Dovi won as many races last year as Marc because it was a "perfect storm", what is the message in this statement? Oh yeah, it's unsustainable! That is he was lucky to even be challenging Marc, something UNEXPECTED. That is, he is the UNDERDOG to try and duplicate the challenge, 'little chance of winning' against the championship favorite: Marc Marquez!
un·der·dog
ˈəndərˌdôɡ/
noun
noun: underdog; plural noun: underdogs
a competitor thought to have little chance of winning a fight or contest.
You couldn't say, well, maybe you're choice of description wasn't entirely reflective of the reality, you preferred to double down. Yeah, you're right, let's agree to disagree.
If you live in a glass house don't throw rocks.