We have to remember that all recent new stock has had major issues as such. Cant just shut off the 332s just cause they have plagued mechanical problems
But you can on the grounds that -
1) They’re owned by Heathrow Airport and not a ROSCO. So for them to see any useful mainline use outside of HEX one of the ROSCOs is going to have to put its hands in its pockets and buy the units off Heathrow - if Heathrow are even interested in selling them.
2) They’re not fitted with mandatory safety system to operate anywhere other than Paddington - Heathrow. Once that ROSCO has bought them outright they then have to pay to have TPWS fitted.
That’s the stuff you have to do before you start thinking about mechanical condition, interior, compatibility with other fleets and so on. Why are Porterbrook or Angel etc going to spend millions getting 14 clapped out EMUs to that point when they’re storing perfectly serviceable, already compatible EMUs left, right and centre.
Sometimes stuff gets scrapped before its time. It may seem wasteful from the comfort of some armchairs; but there is zero economic case to making these units fit for ordinary mainline work. If there wasn’t the glut of off-lease or soon off-lease stock on the market it may be a different story. But there is, and therefore it isn’t.