Its true they could. I think of it like auto repair shops. Here is something really valuable to your daily life, and you want it taken care of properly, but how do you verify that the person you are talking to is honest and trustworthy? You could buy the factory service manual for your car and read it cover to cover, with digressions into the parts which are assumed to be known by anyone servicing a vehicle, and then you could evaluate an auto mechanic's answers based on a ground truth of the service manual, but how many people actually do that? 1% ? 10% ?
In my experience in the Bay area with people who suddenly have more wealth than their friends and family ever did, there are two ways that people seem to split. Either they start splendiforus spending because they are "rich" or the start calculating what sort of 'burn rate' they can support drawing down at a rate of anywhere between 2% and 10% of their net worth. Using the 4% number (which used to be the standard before the great recession knocked it back to 2% for more conservative savers).
One of the things that people usually don't think about deeply is that money in the bank pays you, things that you own cost you. A car needs gas, a jet needs maintenance, a home needs gardening. And when you scale up the 'thing' you scale up the cost. As a result if you live what you perceive to be a 'rich' life you may find its sucking your wealth away. There are lots of studies on lottery winners which show this effect.