Sooner or later every developer hits the situation where someone proposes "rewriting from scratch".
Probably 1 in 10 such situations have merit. Probably 1 in 10 of the merit ones will be successful.
Knowing if you are in the 10%, and the 1% is kinda the skill. For the 9% starting from scratch may have merit, but be unachievable for time or resource reasons. For the 90% it may sound like a good idea, but we'll keep selling (and developing) the old thing in the meantime so you never catch up.
But it's a good gig for developers. You can write code for ages without ever having to ship. I know of one rewrite that started in 2006, and they'll be switching over "any day now".
Of course a rewrite is possible. You only need to answer 2 questions; A) do you want it? B) can you afford it (in money and time?)
Incidentally I (successfully) did a rewrite once (albeit that it was to change platform.) But I stipulated that it would not be backwards compatible. Not the data. Not the UI. I insisted we, um, well, start from scratch ....