If it was crazy overpriced (first checked amazon just to see and got a shock, though it was the collector new in box type deals so eh. Ebay sold listings are high for an old game but not crazy, about in line with what I would expect for a failed console, a Nintendo one too, and less than well received at the time game from a legendary franchise) then it might come down.
As far as coming down from £15 to £35 range to £5 or something more modest in line with many old games then I very much doubt it.
Prices for this sort of thing is the sort of thing I follow along with and make something of a study. If the new version utterly obviates the old one then it can drop prices (at least until that becomes a rarity -- if we are sticking with gamecube go have a look at prices for skies of arcadia, originally a dreamcast exclusive and one of the first quite modern 3d console RPGs, later remade and sold in limited numbers on the gamecube. Or maybe the zelda N64 ports to the gamecube. Wind Waker on the other hand saw something of a drop off with the later releases). However here we have a playable but by no means great version on the Switch, that for now at least is limited edition.
It is also reasonably popular with the glitch and speedrun communities so they will probably keep demand fairly high for the originals. Haven't checked to see what versions are popular this minute and if they change so you might be able to go a different region to what they favour (usually such things are first run Japanese or US releases owing to more bugs and higher framerates).