I like your idea of comparison within your era to make the analysis dimensionless. But how do you get from that to Laver looking like the greater player? I'm not instantly disputing it, do you have data to support that? Intriguing
Well, that would require a huge study - and maybe some day I'll do it. But in the short hand versions of different ranking systems I've played with, Laver just ends up better in almost any way I can think of. He was more dominant within his era than Roger was in his. It isn't hugely different, but Laver definitely has the edge.
For example, TennisBase.com has their own ranking system which I find quite useful for stats and rankings before the Open Era. It isn't perfect - if you look at their
all-time top 100, there are some questionable placements (e.g. Connors and Lendl ahead of Sampras), but that's part of the problem when you rank based upon conglomerating records with no way to adjust for peak dominance. But still, there is no other source or way to rank players before the Open Era, other than
who sports writers agreed were the #1 players each year, which was pretty subjective. Anyhow, TB has Laver as #1 in 1962, and every year from 1965 to 1971 - that's eight years, compared to Roger's five at #1. Or if we look at Slams, he won 17 of 26 he played in (including pro, amateur, and Open), from 1962 to 69, a 65% conversion rate. Roger was slightly better in his very best years, 2004-07, winning 11 of 15 (73%), but that's only four years compared to Laver's eight; if we extend Roger to include 2008-09, it's 14 of 23 Slams (61%), but to get his best eight year span we'd have to go 2003-10, which is 16 of 31 (52%).
Laver also won more than twice as many titles (200 to 89); even if Roger plays for 2-3 more years, that number will stay at around twice as many. Of course it is hard to compare those titles, and TB considers only 189 of Laver's to be equivalent to an ATP 250 or higher. And of course this is an example of how you just can't compare certain things across eras; Laver won 22 titles in 1962 and won 15+ titles in a year seven times (within the 61-70 span); Roger has never won more than 12 (2006), and only won more than 10 three times (2004-06). But consider just how many tournaments players played back then; in 1962, Laver played in 38! So he won 22 of them, or 58%, compared to Roger winning 34 of 49 tournaments from 2004-06, or 69%.
We could go on and on, but you get the point. Both were very dominant, but Laver even more so.
On a side note, TB has Bill Tilden being #1 for
13 years! Or all but two of every year from 1918-32.
Players with 3+ years as #1, according to TennisBase.com:
13 Tilden
8 Laver
7 Gonzales, Wilding
5 Sampras, Federer, L Doherty
4 Djokovic, Lendl, Budge, Ritchie
3 Rosewall, Borg, Nadal, McEnroe, Connors, Riggs, Pim, Barlow
You might note they have Sampras with only 5, rather than the ATP 6. That's because while they mainly align with the ATP rankings from 1973 on, they do differ slightly and actually give #1 to Rios in 1998. They're also better at ranking the 70s, giving Connors only 3, with Ashe, Borg and Vilas each getting one of his years. Connors earns one back from McEnroe in 1982.