Ever notice how those guitar strings optimized for "drop-tuning" have the three bottom strings thicker than the "standard" set?
For example: D'addario's Light Top/Heavy Bottom set, tuned to Standard E
Diameter
Tension
Item#
Note
inches
mm
lbs
kg
PL010
E
0.010
0.25
16.2
7.35
PL013
B
0.013
0.33
15.4
6.98
PL017
G
0.017
0.43
16.6
7.53
NW030
D
0.030
0.76
25.0
11.34
NW042
A
0.042
1.07
26.3
11.93
NW052
E
0.052
1.32
22.0
9.98
Take a look at how the bottom E actually has less tension compared to the D and A string. Now, this analysis was done for standard tuning, not drop tuning: since drop tuning requires to down-tune the low E, you'll end up having even less tension there than when you tuned it to standard (obviously). But they also make the D and A string thicker compared to the "standard" set, making the gap between tensions even higher!
A lot of metal guitarists (like me) also prefer to dig on the bottom strings harder, which is also why these strings need fixing (imo). I don't personally mind having the B string looser, as I tend to bend that string often, but I see no benefit in having the low E lacking tension.