You must be retarded. There's no other explanation.
First of all, Conor isn't a "legit 170+ guy". Conor has fought 3 times at WW where you're allowed to weigh in at 171 for non-title fights and came in at 168 twice and 170 once.
Second of all, Wilder didn't weigh in at "207 vs Fury". You literally made that up. He weighed in at 212½ lbs, which is still exceptionally low for him. In his last 10 fights, be was heavier than 220 lbs 7 times.
However, this is when you went full retard...
Alright well first off I agree with a lot of what you are saying, first guy I'm responding to. Yes Conor weighed ~170 lbs but he's not a Welterweight, he's not cutting virtually / literally any weight to make 170. He's walking around at 170 (not THAT lean either), he's really more of a gigantic featherweight or a normal lightweight.
Wilder on the other hand from the research I did (on top of prior knowledge) weighs ~210-230 pounds, but has admittedly struggled to keep on weight or add weight. He was light against Fury and Ortiz recently, but let's just ballpark it and say 215-220 walking around.
Yes either way that's 45-50 lbs, and we can say 40-50 lbs if we go 210-220 for Wilder. A difference here is also that Wilder has bulked up to 230-ish where as McGregor cannot or does not (for whatever reason) bulk up past 168-174 max. So yes we are talking a 40-50 lb gap.
To respond to OP guy:
1. No-Gi is obviously more advantageous for Wilder or any less skilled/experienced opponent in BJJ. Having a Gi just gives a mechanism to lock someone down, hold them down, inhibit movement, and adds more technique to the mix. No-Gi definitely allows athleticism, power, strength to shine more in general.
2. I question if McGregor is a legit "brown belt" in BJJ, but whatever belts don't matter all that much and he's obviously at least a "purple" + a good athlete and has a ton of experience. Regardless...on to the next point.
3. Haven't we already answered this question over 20 years ago? UFC 1 and early UFCs, the Gracies from Rickson to Royce, etc. We've already see it. Someone trained who's good is going to beat a bigger, stronger, more athletic opponent who is untrained 99 to 100/100 times, and since this is grappling only its 100/100 virtually.
4. But Wilder IS an elite world class athlete. So I do agree with someone else's point that he could get REALLY good within a short time, like give him a year of intense 6-7 days a week, multiple session training in grappling/BJJ and he might destroy McGregor that quickly, I believe he probably would. Conor is a "brown belt" but how good is he really? I'm sure he's good, but he's not Gordon Ryan / Cyborg / Gary Tonon / whoever top level.
5. Expanding on Conor, again I don't know for sure about his brown belt or how good is actually is...but I do know that MMA guys and girls get belts gifted to them based on MMA wins and fights, not just how good they are at grappling. For example, I question how Amanda Nunes is a black belt in BJJ when she couldn't (or didn't) pass a wide open half guard for 15-20+ mins against Carmouche, or advance position, or sub her, and almost getting sub'd by a retard level grappler for that supposed level of competition.