Do you think it is still feasible to invest in Monero for the long run or should I wait for another dip below $300?
Just buy gradually. If it does dip, you get some cheap. If it doesn't dip, you at least get some. At this point, I think it will take a serious governance lapse and a major software vulnerability to interrupt Monero's rise to the position of premeire global digital currency.
It's hard to say because of the number of stealth coins coming out now. There's a lot of competition.
Almost all of them are doomed. Only dash and zcash compete meaningfully for the economic niche, and both are much riskier, due to governance, technical and economic problems. Hence XMR leadership.
The rich get richer and the poor get poorer - it is a fundamental law of network economies.
Occasionally, a poor person smart enough to get in on the ground floor of something like monero stops being poor, and that's what I like about it.