"Entirely possible", yes, but likely? No. cali, there are always exceptions to the rule, and the "rule" in this case is just a normative trend. The trend is that players take a half step back around age 27-28 to what I call a "late career plateau," then decline sharply at age 32. I've offered tons of numbers to support this - its just the historical trend. Not an opinion but what the numbers actually show us.
One thing to consider, though, is that it seems that "second tier" players are more likely to have a spike in their late 20s than true elites. The only exception that I can think of is Andre Agassi, who had his best year at age 29 and was #1 as late as his age 33 season, remaining in the top 10 until age 35. But we can't ignore context; Agassi's age 29 season was in 1999, when Sampras was struggling and there really weren't any other great players. Edberg and Becker were gone, and the next tier was Kuertan, Kafelnikov, Martin, etc - all very good players, but no true greats.
Ivan Lendl is another who didn't really start showing signs of decline until after his 30th birthday, and obviously Jimmy Connors maintained a high level deep into his 30s, but both of these guys were at their best in their mid-20s. Then we have players like Vilas, McEnroe, Wilander, Edberg, Becker, Courier, Sampras, and Federer who started to decline sometime in the age 25-28 range. Not to mention all of the lesser elites that show the same pattern.
I find players like Ferrer and Wawrinka and Haas to be inspirational and good reminders that all trends can be "bucked," but again let's be clear: they are exceptions. Most players start a slow decline around age 27-28 and then fall off a cliff sometime around age 32.
But it might be worth investigating: What makes a player remain in peak form until 30 and beyond, even improve around 30 like Ferrer did? Ferrer got started late, so maybe he simply has more in his tank, and Haas missed a lot of time. But I think there must be other factors. Determination? A training regime? Etc.