It is an interesting comparison (hence the long post), but there are a lot of variables that make it not so clear cut.

The facts are, as others mention, pretty much all our better players will be in the main draw, it's very rare that we will have a top 200 player having to go through quals, and we certainly won't have Q seeds, like the USA had 4 this year. The USA boosted 5 players from those who would be in the qualifying positions to a MDWC, with a mixture of very promising young players (the obvious candidates) and those in good form like Ahn and Di Lorenzo, but they still had McHale who was 4th Q seed, Lepchenko and Townsend also as top 15 Q seeds, and Gibbs, who was a low seed, so although 2 did actually land in the same section, most of those would have gone in with realistic hopes of qualifying. They had 9 (of their 20 in qualifying) in as QWCs who generally wouldn't have too much hope of qualify, especially the younger junior players, although again, these type of players will tend to be better than our equivalents given the respective landscapes of the 2 nations, so not unheard of.

If we break down the Q draw: https://en.wikipedia.org/wiki/2019_US_Open__Women%27s_Singles_Qualifying#Draw

Q1 - Junior QWC Navarro - drew top seed Rybakina in Q1 (recent WTA title winner and in top 70) and got absolutely hammered - very little chance
Q4 - seeds McHale and Gibbs as well as Anderson - so only 1 could qualify directly. Gibbs ended up in the main draw*
Q5 - Lao, direct qualifier, not in great form
Q6 - 2 QWCs in the section, met in Q1 (so one out, one through), one actually did qualify, but then it was young Dolehide who has a huge game, and was just outside the top 100 last year but had been struggling in 2019, but by the time Qs started, her ranking was high enough for quals anyway as she won a US W60 title (Concord) the week before, so confidence was obviously returning.
Q7 - Vickery and a QWC, Vickery might have thought she could qualify, but wasn't seeded
Q8 - QWC, although it was Duval who beat Harriet a couple of weeks ago, so might have thought she had an outside chance, lost in Q1
Q9 - A 14 year old QWC who won their U16 Nationals (our Angelica won that in 2017), lost in Q1
Q10 - The 2 QWCs, who Harriet dispatched of both. Baptiste was actually favourite to beat Harriet at start of play, so had a chance, but still a tall ask to qualify
Q11 - seeded Lepchenko who got to the FQR*
Q12 - Unseeded Kiick - might have had a chance, lost in Q1
Q13 - Seeded Townsend and Ann Li - Taylor qualified
Q14 - One unseeded player (Arconada), lost in Q1
Q16 - Unseeded Muhammed who actually reached FQR and that 15 year old QWC who beat Katie S.

So given the way the draws panned out, they could actually only have had a max of 13 to qualify directly and that included Navarro, that 14 year old, and a few dispensible players who there probably wasn't too much hope for going into it, which reduced the realistic chances further, although there's no doubt the USTA would have been looking for more than 2 direct qualifiers, or even 4 ending up going through.

*Although Lepchenko and Gibbs didn't qualify directly, in the era of Katie B turning up to Paris and delaying her withdrawal, yet still hasn't played since, or Schmeidlova undergoing surgery just after Wimbledon but still timing her withdrawal, or even a former slam finalist like Zvonareva (who did exactly the same at Wimbledon to open 1 of the 3 LL spots there) purposely delaying their withdrawals, there's always a chance of LL spots opening up, so if you are a seed, especially a higher seed like Lepchenko, there's always a decent chance you will end up in the LL pot (Harriet would have had she lost to Wang), so while certainly far too risky to potentially tank your FQR, at least they put themselves in contention to get in via the backdoor by winning 2 matches and thus giving them a decent chance of ending up in the draw (Heather...).