You are right, the city of London and the LSE are gradually losing favour and this has been sighted as a partial justification for the cash ISA caps. Trouble is, as you say, in the connected world where every man and his dog can pull out his mobile and invest in pretty much any market in the world, why would capping cash ISAs mean people would suddenly choose to invest in the FTSE ?
I think its possibly just another cash grab from the middle classes, the treasury need more coming in and the rich are too mobile to snare. Capping cash ISA's means people who value the security of cash savings will leave the rest of the money in "normal" savings accounts and pay tax on the interest earned over their tax free allowance.
News flash... If you can afford to pay into and isa after mortgage/rent and all other costs of living, you *are* the middle class.
Edit.. Also the treasury has nothing to directly gain... You don't pay tax on ISAs!
The idea is, it results in more people investing in UK business, which means more UK business growth which benefits the wider UK economy in more general terms.
That indirectly benefits the treasury, as uk business doing better means the business pays more tax as they are making more money, and theoretically creating more jobs as they grow, etc.
It's not a terrible idea on the surface, depending on if, or how it's implemented.
The devil will be in the detail as always.
It's quite correct to assume that some people will simply not invest in stocks and shares ISAs full stop because 'too risky' or whatever.
Is suspect the government will either do nothing, or simply say you can't put 20k per year into cash ISAs, they may limit it to '£x' per year to push people into stocks and shares.
I'd be incredibly supprised if they forced individuals to only invest in UK stocks though. That would be insanity on a number of levels..
Investing in a UK ETF for example, is a lot more risky than an all world ETF so people might not bother at all, which would achieve the polar opposite of encouraging more people to invest.
Give this a watch of you want to give yourself nightmares lol,