Different timeline, but the same resources. Both Starfleet and the KDF were fielding the same ships in battle. Three of the big BOPs were a match for a Galaxy.
The problem with this thinking is that it assumes the resources are being utilized in the same way. That the Federation was getting its butt kicked by the Klingons in an alternate timeline has no bearing on the events of the primary timeline. Even change of the smallest degree could have broad implications in the creation of a new temporal events sequence.
The trouble is that we know little or nothing of the sequence in question. We're shown only the events of "Yesterday's Enterprise." Picard indicates that Starfleet is on the verge of surrendering, but we know little of how things got to that point. One cannot assume that every individual who played a key role in shaping the Federation in the primary timeline would have the same role in the alternate timeline. The Enterprise-D
is but a single vessel. We have no way of knowing what the Federation as a whole looks like beyond the fact that it's losing the war.