- Price of housing and associated maintenance keeps rising, and so do small jobs like fixing plumbing, gardening, etc; - You can easily avoid paying VAT if you know how to, so that's a 20% increase, or even more, if you can benefit from social services (e.g. since you don't earn a lot, you pay less for several services); - Doing the fixes yourself saves lots of money; - Avoids several burn out and mental health issues related to stress such as academia, bullshit jobs, etc; - No need to spend years in school, so you can save money earlier and invest it.
One disadvantage is that the barrier to entry is somewhat low; but the PhD students also have to compete with cheap international labor, so in the end, someone 25 years old that just left grad school is happy to earn, say, 2000€, while someone in the trades can easily make 200€/day with just one appointment.
So, if you're physically fit for blue collar work, there are currently few reasons not do it.