[Lavery]

  #1 Interest rates are as low as they have been in an extremely long time, people/institutions want higher returns so they are putting money into vehicles with higher returns(stocks).

This isn't wrong, but it's also worth noting that (regardless of return preference / risk tolerance), higher stock prices are also, partly, a consequence of low interest rates. Stock markets are many things, but one thing they are is a discounting tool, and the discount rate you use is informed by market rates elsewhere. If interest rates are zero, simplistically, equities are the sum of their related cashflows for the next indefinite period of time.

(I'm aware there are other premia I'm not including, but, simplistically)