Submitting paper when leaving academia?
I would say, yes. 

If the results are worth publishing, then the world should know about them.

That said, even if the paper is accepted, it is likely that you'll need to make minor or major revisions. If you do not expect that you will have the time to do this, then ultimately the paper will be rejected (or simply just vanish). So you need to consider whether you will, in 1, 2 or 3 years (or whatever the journal turn around time is) be in a position, mentally and otherwise, to address the review comments. 

The other option is to archive the paper on arxiv.org and hope that interested people find the work – for the good of science.