How strong was Samuel Reshevsky

At his peak, would he be in top 10 today?

no

No, because Sammy Reshevsky was weak in the opening. Pal Benko used to say that it was hopeless trying to help Reshevsky prepare openings, because he just never could remember his preparation at the board. Today opening preparation is key. That said, today's penchant for seeking out the less mapped-out areas could potentially have helped him. Also, the increment system would have been great for him.

he was good enough to have become world champ at his peak

Was he though? Because he didn't... 

neither did caruana and keres and korchnoi and bronstein lol

No, he wasn't quite good enough. The American before Fischer with a real potential was Reuben Fine, not Sammy Reshevsky. Don't get me wrong, Reshevsky clearly was top five in the world for at least a decade after World War II, but his opening knowledge was poor and he was chronic time trouble addict to boot. No time trouble addict has ever become world champion.

A good second rate GM.

No, still a good world class GM.

Yes that's true, but nobody mentioned these other players and I was responding directly to your incorrect point about Reshevsky. 

Reshevsky was top 10 in the world almost all the time between 1935 and 1960. For a good part at the time he was in the top 5. Fischer had enormous respect for Reshevsky's ability. The Benko story is interesting, but when Benko was working with him, Reshevsky was over 50 and slowing down. The main thing to remember about Reshevsky is that it was almost impossible for an American to make a living at chess in 1930-1970 period. Reshevsky took several long vacations from chess while trying to support his family. 

A good second rate world class GM because in those days, all GMs were "world class". Nowadays a GM can be of about the same status as an IM.

I'll concede that Reshevsky is and was under-rated.

Grigory Levenfish made this observation as early as 1939, having participated in the Leningrad-Moscow training tournament. Then Korchnoi made the same observation ahead of their Candidates match in 1968. Reshevsky suffered from these flaws his entire career. Both Botvinnik and Fischer took time out from chess. As for Fischer's complementary views on Reshevsky, let's not forget that Fischer especially early in his career lacked objectivity. About the same time he dismissed Lasker as a coffee-house player (he later changed this view).

Very strong GM, no doubt about it, but the US lost its real opportunity to get a world champ (before Fischer) when Reuben Fine retired. He was a more rounded player than Reshevsky, and didn't suffer from a time trouble addiction. Reshevsky was an incredibly tenacious player, but it was never quite enough.

Top 10 today? Including spotting today’s world elite maybe 60 years of theory and general chess advancement? That’s crazy. No.

He was darn good, though. 

" US lost its real opportunity to get a world champ (before Fischer) when Reuben Fine retired."

This is an argument that can never be resolved, of course. That's what makes it fun! In fact, I believe we've had this same discussion before. In my opinion, Fine's nerves and tenacity were inferior to Reshevsky's. I think it's a great mistake to underestimate how important these qualities are when you get to the very top level, where everyone plays great. But as I said, this is an unresolvable argument.

Fine's nerves and tenacity vs ditto of Reshevsky's are probably a matter for another debate! (I think it was the other way around.)

There is a significant amount of doubt in this completely unprovable statement. 

lol fr