That's weird, you didn't accidentally select one of the other contact files instead of the allcontacts.vcf by chance? It'd be either that or somehow importing to the google account messed up the file, though I can't imagine why the latter would be the case, plus I can't think of many things worse than giving google all my contacts so I won't test if that actually messed up the file.

So long as you haven't deleted all of the individual .vcf files of course, you could try deleting the allcontacts.vcf then run the terminal command again,
Literally all you have to do after running the concatenate command is open the allcontacts.vcf file, select the "mark all" button down the bottom, then click the import button.

It should look like this:

Then:


It shouldn't look like this:


If it does look like the last image, then there's only one contact in your allcontacts.vcf file, which doesn't make sense if all of your contacts successfully uploaded to google from that allcontacts.vcf file.

So yeah make sure you didn't accidentally select the wrong .vcf file.