I don't think that's true, I've also been there a few times site seeing myself and have the ability to pick things up quick.
I believe to be a budtender all that is required is knowledge about cannabis and what strains would be best for the customers requirement whether it be for medical reasons or to just get high. I am starting to think it's going be hard to get though since it's a dream job for most stoners but then again do most stoners know much about cannabis.
You are over glorifying a job in the service industry, trust me I am passionate about cannabis and have been for many years and when i was younger i thought a CS job would be cool and a good use of my passion.
Since living here for 1.5 years i have watched many new BT's come and go, when they first arrive they are enthused in their jobs, eager to learn, happy to see boxes of weed, happy to talk to customers and try and make recommendations.
Almost always about 3 weeks into their job they have lost enthusiasm, they hate looking at the boxes of weed they cna't smoke and their boss makes a pretty penny from a 50% mark up
, they resent the tourists, they resent their regulars who can come in and afford supply, they resent their long boring hours of serving the same shit over and over again. recommending crap to tourist only to have them ignore you or question your choices, the hardest part for me would be recommending half the shit the coffeeshops sell as high grade weed, when in reality it is fresh unflushed commercial shit.
Basically it's not a great job, few stay passionate and the ones that are happy are normally the owners.
edit: saying that i have met a few who have been here a long time and are true honest people who loved their job, although no longer working due to their shop being closed during school hours now and due to close next year. Amsterdam is not the place it once was, many of the old faithful are moving ship to spain or USA.