@shakey even if they could get insurance for it and have it work in a way that made everyone happy, they're not obliged to run it. It's a private company, with an individual at the helm who can do whatever they want - it's like a football team, you can sell your players if you don't get on with them, if they're not performing or if they are a pain.
They did spend a huge chunk of money trying to get it to work, but that caused a ton of other problems that I think they didn't have the will, resources or financing to resolve. I know Icon wasn't built in the same spot as Wild Mouse and I know many (ourselves included) don't think it's a worthy 'replacement', but they did spend £16m on a new coaster as they retired the mouse.
The ride closures over the years are pretty far reaching and were for a multitude of reasons :
Post-Wristband
2000 - Cableway (Valhalla played hell with the cable)
2001 - Veteran Cars (converted into Convoy)
2002 - Safari Ride (no idea, crap)
2003 - Millennium Bug (moved to Southport)
2003 - Vikingar (low ridership)
2004 - Turtle Chase (baffling removal)
2004 - Big Apple (also installed post-wristband)
2005 - Black Hole (I don't think it 'fit the brand' - space required for 4D cinema
2005 - Whip (sad, sad closure)
2006 - Alpine Dodgems (two sets of Dodgems fairly excessive)
2006 - Drench Falls (Sigh)
2006 - (Wall's Cornetto Soft
) Spin Doctor (Low capacity, terrible reliability, high staffing)
Post-Entry Fee
2008 - Ellie's Garden Caterpillar (area reconfigured, I guess Nick Land was in the plans at this point)
2008 - Griffin's Magic Dragon (area reconfigured, I guess Nick Land was in the plans at this point)
2008 - Circus Clown (area reconfigured, I guess Nick Land was in the plans at this point)
2008 - Noah's Ark (H&S mooted, but not really sure)
2009 - Superbowl (No idea - replaced by Sculpture Gardens)
2009 - Trauma Towers (tinder box)
2010 - Space Invader 2 (saleable asset, removed for never built Phase 2 of Nick Land)
2010 - Boats (removed for Nickelodeon Land)
2010 - Helicopters (removed for Nickelodeon Land)
2010 - Lunar Carousel (removed for Nickelodeon Land)
2010 - Magic Mountain (removed for Nickelodeon Land)
2010 - Mangnus' Mini Dodgems (removed for Nickelodeon Land)
2011 - Bling (one of the few saleable assets that they had - maintenance headache to boot)
2012 - Monorail (maintenance headache - shame)
2016 - Bridgestone Go-Karts (removed for Icon)
2016 - Tetley Tea Cup Ride (not sure - old)
2017 - Wild Mouse (we'll probably never know for sure)