You may surf the internet a bit and obtain photofacts of Maduro's wide support:
So, "dictator without people's support" is just a myth. But does no one in Venezuela supports Guaido? It won't be fair to say "yes". Guaido's supporters are concentrated in rich districts of Caracas. They are what you call "upper middle class". Parts of the old, before-Chavez Venezuela, from the times of a banana republic. That was logical - according to the Monroe doctrine, which is what Bolton now tries to revive.
That is important - without understanding what is the Monroe doctrine, it's impossible to understand why controlling Venezuela is so important for the US. As you remember, the doctrine claims the whole of South America as the US's (and only the US's) exceptional influence area. You can dive into late 19 - early 20 century history - time of full power of that doctrine - to understand term of a "banana republic". Or just open O'Henry's stories - "Cabbages and Kings" will give you such understanding. In fact, in those times there were no independent countries - just territories for US business.
Another point to low Guaido's support is a lack of support from the army. Venezuelan elites are now under very high pressure - just read John Bolton's twitter feed a bit. Do you see those endless claims to army to betray Maduro? Do you now why John Bolton has to persuade them himself? Because Guaido is in terribly in need of any army supporters.
Just imagine - the US, one of today's superpowers, cannot change regime in a country near its borders. Remembering regime changes during the Arabian spring, the regime changes in Ukraine and Georgia, and attempts to change the regime in Syria, we cannot say, that US has low skills or low resources. Doesn't this describe Guaido's level of support? Even Guaido himself accepts it, in some strange manner, but he does.
Also, if you already opened John Bolton's twitter, you may notice, that from some point, phrases about 'democracy' disappeared, John starts to be direct in his claims - "Russians should leave!". Without spells about "Venezuelian people" and "democracy", "elections" and so on. Just problems in US zone of influence controlling. Did you hear about Guaido before all this? No. He was just dropped out of the box, claimed as "Popular leader" and supported. No matter that there are OTHER opposition leaders - that's really so. But US chose Guaido. Why? Don't know, really. Maybe he is more guided. Don't know.
And about economics. Many claims about "Venezuela's economics is failing". That is true. And now there are US sanctions on it. But do you know how much time are sanctions in action? Let's see: Oh, my god, sanctions are in action for a very long time - from 2014! Sanctions also affects even medical supplies. Strange, that US press blames Maduro about medical supplies shortages - they should know, that the US itself stopped selling them, shouldn't they?