That looks nice. If I was braver, I'd daily drive that! So many factors here including Brexit however I don't think Maserati's current brand positioning is doing anything for the older cars now. I'm seeing diesel Ghiblis on 14 and 15 plates now going through the auctions for £16k ish. Your average punter wants a newer car to show of to his neighbours, who have no idea of the difference between models. That's why BMW will de-badge a 318 for you and cover it in M badges. Why but an 8 year old v8 for 30k when you can buy a 4 year old v6 for less than 20? Most people will go for the brand at the lowest price, like a fake handbag.
Only by building fantastic, aspirational cars, will you drive up the value of the "lesser" models and add nostalgia and it's value to the old stuff.