It was already govt-owned once before, as a part of the British Leyland mess.
If it made sense as an investment then presumably private backers would be queueing up to pump money in, to make tons of future profit.
JLR were doing OK once. Jag made some nice looking cars in the 00s, once they stopped making inspector morse and tarted up mondeos and just made nice cars that people wanted such as the XE and F-Type. I agree the i-Pace looks lovely too, at least when it's not on fire. Now they've committed commercial suicide with the pink cartoon car and drag act advert. They could now make the best car in the world and most would be too embarassed to drive it.
Land Rovers have been woefully unreliable for at least a decade. Instead of doing the sensible thing of actually fixing things they instead designed about a dozen slightly differently shaped rectangular boxes on wheels, to the point where nobody could possibly understand the model range. They could have instead stuck with a sensible number of car shapes and put their efforts into actually fixing things, and recovered their image.
Or perhaps they're deliberately making crap cars, so owners have to spend more on parts and labour to fix them. Makes short-term profits, but ensures that these customers don't buy another.