He wins only because of a car. Kind of similar to Vettel and Schumacher in that sense but to a WAY luckier and higher degree than both, as Vettel only had the fastest car 3 or 4 years of his career, Schumacher only 5 years of his whole career max, while Hamilton has been in the fastest car 8 or 9 years of his career, and the 2nd fastest all others. Hamilton is basically the only driver in history who had the fastest or 2nd fastest car every single year of his career (most years the fastest). So no he isnt that good. He is pretty good, but that is it. Second rate drivers like Button and Rosburg were roughly his equal in the same car, and all his other teammates (apart from one year of Alonso were he was harassed by the team to ridiculous degrees and still tied in points, so that one doesnt even count) are complete crap and much worse than even Button and Rosburg.
And he isnt that popular, he is mocked by fans in Brazil and Spain, amongst other places, has been booed in other countries. The only place he is fairly liked (sort of) is Britian, and as already noted even the ratings in Britian are lower than before so he isnt even exactly beloved there. Someone like David Coulthard who never won a drivers title and wasnt that successful overall was even far more popular in Britian.
I can't find it right now but on an F1 forum they tried to show how many times these drivers were in a car that could have won the WDC and Schumacher of course headed the list. Hamilton and Prost were a couple behind Vettel a couple further behind, hence 7 vs 5 vs 4 makes sense per their opportunity. Schumacher has been in many fastest or second fastest cars, the most of all F1 drivers in history. Overall I'd say he's also quite lucky. Firstly, I want to make it clear that I think Schumacher was an incredible racer and talent and possibly the greatest, so now that's out of the way I'll explain why. (1) he inherited a vacuum after the loss of Senna, Mansell and Prost to the sport. (2) He received the most blatant help from teammates of any driver in the history of F1 where perhaps only Fangio is comparable; just look at what the likes of Herbert reveals in the recent official F1 Podcast or the numerous revealing chats with Eddie Irvine available on youtube for firsthand evidence, although watching the races is enough. (3) He was allowed unlimited testing, unlike his teammates, in his Ferrari cars (and various machinations of so called Ferrari International Assistance - I won't vouch for its credibility).
The notion that Hamilton had generally crap teammates would be literally ridiculed on any F1 forum. It's Vettel who is questioned for the strength of teammates with many unsure on how to rank him until they see him against another definitively strong opponent who is in their prime. Leclerc will be in his 2nd year next year, hardly prime yet. If he even equals Vettel there will be trouble.
Hamilton is really fortunate to have had such competitive cars throughout most of his career, though he's backed it up with results and quality. It's why Alonso is utterly convinced that Hamilton is superior to Vettel. Nonetheless it's thought by many (I dare say most) that in 2008 Ferrari had the fastest car and the same can be said for 2018, meaning Hamilton has probably won 2 of his titles whilst not having the best machinery. On the flipside he's also lost two titles whilst having the best machinery (2007 rookie season and 2016 vs Rosberg). He's had a car that could win the title in the following seasons: 2007, 2008, 2010, 2012, 2014-2018 for 9. Schumacher in the following seasons: 1994, 1995, 1997-2004, 2006 for 11. So both had had great opportunity, and different perks. Schumacher has made more of his opportunity with 7 from 11. Hamilton is at 5 for 9. IIRC Schumacher won ~56 or 57% of races during the more dominant 2000-2004 period with Ferrari and Hamilton ~50% during an equivalent period with Mercedes, but Hamilton's and Mercedes' period of having a hugely competitive car may last for longer. Will be interesting to see.
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To add:
Vettel: 2009-2013, 2017, 2018 for 7, winning 4.