Worse than that. Ortiz would need 172 extra hits to be a .312 hitter. Over 18 years. So just under 10 hits a year. If you want to stagger them a little based on years he had more ABs than others, sure, but it's seriously like 10 hits a season. Like one ball a month that gets through instead of picked by the second baseman. Either way, a career .287 hitter is GOOD.
Know things that are HUGE? Difference between 309 HRs and 431 HRs (plus whatever he gets before he's done). 7 or 8 HRs a year, every year, is a big number. Especially if you aren't much of a fielder, that's a big upgrade with the bat. Instead of 24 HRs a year, you're consistently doing 35, that's going to win you a few games along the line. (24 and 35 are their 162-game averages).
And where you said OPS, you mean OBP, because slugging is part of OPS. Ortiz and Edgar are about a wash there (933 vs 930)
For fun, post-season stats:
Ortiz: .295/.409/.553/17 (82 games)
Edgar: .266/.365/.508/8 (34 games)
Gets into sample size problems, but similar post-season power, ortiz maintained a higher batting average and OBP over that span. Hrs are a wash based on percentage of games played, assuming Edgar continued at that rate in more chances. And Ortiz batted something like .688 AVG on the way to World Series MVP this year. Not too shabby.
You REALLY can't talk fielding, Edgar was a DH. Legally, he played a little in the field for the first few years of his career. In an 18-game career, he played other than DH in 5 seasons for any real stretch, and all at the beginning. After that, DH all the way. In fact, he played at 3B or 1B after 1994 just slightly LESS than Ortiz shows up in the field today. Ortiz didn't really ever have the couple seasons where he played 100+ games in the field, however. Looking, I don't remember him playing 30-40 games a year at 1B in 2003 and 2004, but numbers say he did. Either way, Ortiz has never been a disaster in the field, he's just in a league where he doesn't HAVE to play there. Since he's not a gold glover, AL teams can set it up to have a good 1B AND a good DH, no reason to penalize Ortiz for it. If the DH wasn't a thing, he'd go out there and play, and be just as middling as most other slugging 1B are. How excited are you about Prince Fielder's range?