That Riker was able to gather a hundred ships in a few days, and mobilize them to the synths' planet suggests to me that after the Dominion War, Starfleet must have maintained a major war footing. Where else would those ships have come from?
Starbases close to Romulan space? They probably were there all along, even back in TNG and the TOS movie era, since that's where they would have been needed, not at tranquil Earth.
Starfleet barely managed to muster 40 random ships at Wolf 359, next door to *Earth*. To assemble these ships either means ships are faster (to converge quickly) or there are more large fleets on maneuvers scattered widely across the Federation.
Or Starfleet prepositioned the ships where they would be needed.
Yeah, I agree, the smaller engagements make for more interesting battles over the years - Yesterdays Enterprise, Way of the Warrior and the MU Defiant off the top of my head - but it doesn't make sense for Starfleet to have a fleet of 30-40 being one of the largest assemblies of ships ever seen.
It should be noted that whenever we saw a small formation of ships, the writers took extra pains to say "Ooh, what a
pitiful force! How come we have so few ships? A damn shame that we were in such a hurry and couldn't bring thousands! Nobody can wage war with just dozens!"...
This is a post-Dominion and Borg Starfleet, they've had years to prepare for future incursions and aren't going to be scrambling around to put together a fleet, mass producing or retrofitting Mirandas from ship graveyards.
On the other hand, if Starfleet could build more ships, it already would have. It's never at peace: in TOS and TNG alike, it's chronically and fatally short of ships, the hero vessel always being the only one that makes it to the weekly adventure in time. Or, just as often, a tad too late.
Blame DS9, which decided to really up the numbers on starships.
No, TNG writers did that. DS9 just had the resources to
show that, too.
Of course we now retroactively have a 7,000-strong Starfleet in the 2250s. Which is what we'd expect anyway; now we just get the dialogue reference to it.
Timo Saloniemi