You’re completely right. I spoke incorrectly, but hold that Jane is a mouthpiece of the author who died unwed.

Bingley and Jane do wed though in a way largely in contrast to the rest of novels depictions of “the game”.

In the eleventh hour of the novel and in a more impulsive ceremony as a sort of ‘double marriage’ with Elizabeth and mr Darcy.

The bingley relationship is another example of the interpretation though because it appears the only one in the novel exhibiting “true love” and compatibility between both parties and is met with opposition from just about everyone else.

I highly doubt that Jane is Austen's mouthpiece. Jane's defining characteristic is her almost preternatural goodness in contrast to the highly amusing flaws of the rest of the cast. I think it's unlikely Austen would use such a "perfect" character as her own stand-in.

Jane's marriage is also by far the least impulsive of the four marriages depicted in the novel. It is the culmination of the longest arc, and the fulfillment of the longest-held hopes.

Is it possible the wedding was external pressure on Jane Austen?

It’s pretty commonplace now that traditional audiences, studio execs, editors, and even other creators push creators in to tropey “they got together in the end” endings. Is it possible that was true then as well?

It seems unlikely. Elizabeth's principle objection to Darcy was that in detaching Jane and Bingley, he had been the "means of ruining, perhaps for ever, the happiness of a most beloved sister". Darcy's correcting this mistake is therefore absolutely essential to reconciling himself to Elizabeth. The Jane-Bingley arc is also the longest in the novel and of secondary importance only to the Elizabeth-Darcy arc. The novel could not really have had a happy ending without resolving it.