The main query appears to be -- Will the margin calls cause...

The main query appears to be -- Will the margin calls cause widespread slump in the West?

Well margin calls are triggered automatically and instantly with the need to place more funds in account and/or sell shares at market within hours.
I believe most margin calls have been satisfied by placing more funds in account.

So any damage caused by market slump and margin calls is history.
It will only another serious slump in market - say a sudden 10% drop in indexes - that margin calls will be activated again on a widespread manner.

I do not think the margin call effect is sufficient to cause widespread mayhem in the West.
Most investments are institutional and long term non margin accounts.
Nearly all margin lending accounts have sufficient "margin" to keep them safe even in - say - a 10% slump in market from previous lows.

Most margin borrowers - those with a modicum of common sense - will have ensured their borrowing percentage has been lowered to a safe position since the market slump.

The bottom line?
Margin call effects are insignificant in the overall economy.
Make for an occasional one day excitement and the occasional ABC type action.

Things should soften in the West as interest rates increase, living costs surge and markets continue to stay under pressure.

The effect will be varied and specific.
Premium houses will hold value and probably increase in value.
House prices in mortgage belt areas will slump.

And so on -----.

If anything will impact on cars, boats and housing it will be over commitment on borrowing to fund the life style - brought to account by increasing interest rates and costs of living.
Not margin lending calls.

The sky has not fallen in.
And is unlikely to do so!