right now the easiest and most reliable way to get BTC is simple to buy some in the countless exchanges that are available in the world. mining is no longer an option for 99% of the people.

what kind of investment? putting all their savings in crypto is too risky ofc, but taking 10-20 percent of their money and invest in btc is a great thing to do as they will be able to make profits that no other investment will yield.

so what is the current number of validators?

it's gambling only if trading for short term. noone can predict price for short term, but long term investors are no gamblers of course.

transaction fees doesn't depend on price of the coin, but on the load on the network, and the costs that mining involves. LN will lower the fees and they won't change much even if the price is 100k.