I'd heard somewhere, months ago, that McConnell wasn't really doing much to speed things up either. He was allowing things to go slowly without forcing the democrats to all show up and push the issue. The republicans could try to make things speedier and force more democrats to actually attend the senate sessions in order to procedurally slow things down, but they were allowing the procedural slowdowns even when republicans had the numbers in attendance to force the speedier process.
Of course maybe this was just some backroom negotiation between him and Schumer to not make everyone be constantly in attendance. A sort of "Here's how the fight would go, so let's just not and pretend we did."
Also to go along with that, I believe Schumer was allowing things to happen unopposed that wouldn't normally be in democrats best interest.
In any case, washington politics.
"Washington politics" is an accurate statement, but it's incredibly rare in the Senate for senators to be forcibly sat down and run through floor activity. Almost every vote takes 20+ minutes because all the senators need to amble in from whatever fundraiser, constituent meeting, or whatever they're at. (In the House they usually stack votes so that the first is 15 minutes, then the rest are 2-5 minutes. And that's with over 4 times as many members.)
Under the new rules, there's nothing (within the normal bounds of Senate comity, at least) that Schumer & co. could do to slow things down further. The debate limitations put into effect earlier this year really throttled the avenues of resistance.
And forcing the minority to sit down, shut up, and vote also forces your own majority members to do that -- they're not any happier to be there instead of fundraising. Especially if there are more majority seats under threat than minority seats, it's in McConnell's interest to not make his own members sit around voting all the time.
[Edit: yep, hundreds. Though a good portion of those are probably non-controversial ones confirmed by unanimous consent.]
Based on that link, looks like the number of nominations that the senate has to confirm really isn't out of line with previous presidencies. Trump's first year was a LITTLE higher than average on most first years in recent decades, but not absurd. This year seems to be a little below average if it continues at this pace.
Might be in part because the debate change was only this April? So only about half the Senate's term thus far has been under the new rules.
From personal observation (part of my job is tracking what the Senate does), this year has been spent predominantly using floor time for nominations instead of legislation. And with the 2-hour debate rule in place, they're able to do many more per week than they had previously. They're not going at maximum rate, but they're doing about 8-12 per week instead of 3-6.
Does indeed to seem that the numbers fit the trend you state, which strikes me as odd. Could be that the number of non-controversials (i.e. those that can be dispensed with en masse via a single UC agreement) is lower? Not sure.
EDIT: I should note that using floor time for nominations instead of legislation isn't really that new in the Senate. Majority Leader Reid frittered away most of... 2013? 2014? doing the same thing. Even after using the nuclear option, though, he left in place the 30 hours of post-cloture debate.
AND A FURTHER EDIT: I should
also note that it's pretty common for a large cluster of nominees to get UC'd at the tail end of a year, so there's usually a spike in numbers around then. That's because nominations expire at the end of a calendar year, so the majority & minority leaders usually strike a deal for handling a bunch of 'em. Of course, the number of expired nominations per year was much higher than normal in Trump's first and second year...