I analysed the UK Hoverflies a while back and I found that the average observation required just under 2.5 IDs to reach research grade including the original ID. I don’t known how that varies between taxa/location. I suspect that the 60,000,000 IDs quoted by the OP does not include the initial ID-on-upload (there can’t only have been 10,000,000 IDs-for-others), so it would need 75,000,000 such IDs to ‘keep pace’.
I also worked out that, in Animalia globally, 70% of IDs are made by 0.16% of identifiers (roughly the top 500). I wonder if more could be done to encourage a small amount more identifying by a larger cohort of people in the lean winter months. Perhaps some people feel there’s no point identifying if they can’t do a lot. But it’s actually a great way to keep in touch with nature - and with iNat.
Nevertheless - great work to everyone involved - both those observing, and those IDing, and those doing both.