I'm currently reading A Short History of Nearly Everythingby Bill Bryson and realising that there are many practices that we now think of as new that are actually darn old:
1. Self publishing
Lots people that wrote books self-published them or funded the printing in days gone by. Some lost a fortune as a result.
What we now accept as the "traditional" publishing system actually replaced self-publishing and we've now come full circle.
2. Working past retirement
Most people stopped working when they died or when they simply didn't have the physical capacity to. This was especially true amongst the educated classes - they worked for the joy of working and discovering new things. They were many tinkerers.
Seeing retirement as a time when you completely stop work and get paid money anyway only came in post-world war 2. Regulators decided it was humane and fitting for the "civilised" world to give the elderly a break.
It's an ideal situation that is in fact completely untenable. To support retirees you would need an ever increasing class of working people; with the decline in both birth rates and death rates this won't happen.
3. Working from home
Many scientists in the old days worked from home. I imagine they rolled out of bed at 5:00 or 6:00 a.m. and continued where they'd left off the night before.
Now we're trying to revert to this old way of working - funny.
Admittedly, you will find that many early scientist came from privileged backgrounds and were unbound by the need to earn a living wage.
4. Being a jack of all trades
A lot of entrepreneurial literature talks about how the ease of technology means the same person can do lots of previously "specialised" tasks. This is true but people in the olden days didn't specialise either.
They didn't have the advantage of all this technology we now have but they all dabbled in a multitude of trades. If you look at profile of distinguished people of old you'll frequently see "Biologist, Chemist", "Writer, Geologist". Amongst the writers you'll find many people that wrote books on very different topics - "Economics, Psychology, Beauty".
On the other hand business schools also espouse the benefits of focusing on just one business. Personally, I think the idea that you'll do better if you just stick to one thing is complete rubbish.
If you've got four start ups on the go because you simply want to make money you'll probably fail. If you've got four start ups because you're passionate about all them and are committed to consistently producing some output for all based on a focused schedule - that's a successful result in itself.
Next time you're confronted with a new idea, know that it might just be an old idea coming back.