Looking at trends 2 or more years, Bitcoin appears to be headed for $70,000 over the next 3 years though it appears heavily bullish right now. Are there people with charts/trends etc taking us to the $70,000 level over the next 3 years?

I'm not sure. Its really hard to tell eveb if it is true that its market value at this moment is continuously increasing since we don't know until when will it have a rate as this high on the increase of its market price. And also 70000$ is way far from its current value which is approaching to 8000$ to be reached within only 2 years from now.
Nope, you're right just try to take the real formula regarding it. Imagine the bitcoin worth $500 - $700 at the previous year and this time it is worth over $7000. Let me say there is a lot of increase around $6500 - $6900
and i can say there will be more increase but no more than $10000 at the end of this year, So the possible thing about the bitcoin's price increase every year will be more slowly. Because the more value on the bitcoin.
2x will be more difficult to be reached from now.