Does Bitcoin can be trusted and reliable? Is Bitcoin a Scam or Money Games like a Pyramid scheme anytime can collapse?

Anything can collapse suddenly, not just pyramid schemes. The US housing market collapsed suddenly in 2008. Of course Bitcoin can collapse. That doesn't make it a scam, just a very, very risky investment. Things that go straight up in a short period of time tend to come down quickly also.

Blockchain-based crypto currencies like Bitcoin are too new to know if they will last. Governments haven't yet figured out a way to get their slice of the pie, and when they do, which will be by taxing and regulating these currencies, I expect a sharp fall in values. I don't expect Bitcoin to go away but I would not be putting my money into it.

once mining ends in the next decade, there is only some vague idea regarding who funds the recalculations needed each time a BitCoin is spent - it's huge amounts of electricity, and at the moment the people doing the calcs get bit coins - I think it's about to burst, but not disappear

Reading some old newspaper headlines from the past century

Candlestick Makers Warn:Danger in New Edison Lightbulb - A Fad

Theater Actors Up in Arms - Moving Pictures Will Cause Blindness, Sterility, a Pyrmid Scheme

Buggy Whip Industry: Danger to Newfangled Automobile Conveyances - About to Crash

Global Banks & Finance, Govts, Gold Industry: New Currency Bitcoin a Scam

Ask the Venezuelans.

Not a scam, but might be going through a bubble right now due to speculation.

bicoins have been around for some time and apparently have proven successful

Isn't backed by anything like a government. can collapse anytime, your call

It's not a scam, but it's definitely highly volatile compared to some other investments. I would look up actual articles about the subject, if I were you.