PoE certainly DOES fully support slowboating, but it sure as shit doesn't reward it.
I never did this and I don't think this is needed. I would even sometimes wait 1 week before starting to play so all the autists that do this can flood the market with tier 2 equipment in their hunt for tier 1, drop their prices to reasonable levels as a result and let me buy those (still awesome items) for reasonable prices and let me do whatever the fuck I want with my builds while playing at my speed. Also the chance for chaos orbs, exalts and other shit to drop is same in lower levels as later (well except maps also have additional quality and quantity bonuses).
Totally a valid "low cost" strat alright.
However, the first week is where it's at if you want to make a good deal of wealth for future big purchases.
In my experience, for any temp league:
1) week 1 = best time to build a future wealth base - exalts are cheap, everything sells for a lot, so if you play a "league starter budget" type of build that can do well on throwaway gear, you will be able to sell everything for a nice markup. It's actually also a great time to buy the NEW stuff that got just released before it's hyped up by some streamer (cough, Mathil, cough) and jumps in price.
Most people playing the first week usually go for "tried and tested" builds and gear set-ups so you can make a good deal selling it to those unimaginative people while buying the future cool stuff.
2) week 2 = economy is mostly stabilised, prices for "mundane" gear start to drop due to vastly increased supply, people mostly figure out what new content (gear, skills, challenges, etc) is worth. The profitability of trading gear goes down somewhat, but it's the best time to start buying gear for your chars. Also, it's the best time to start selling challenges and access to content to people due to increased demand from challenge-hunters.
3) week 3 = saturation. The most amount of gear available for sale, at low-low prices. Most content is readily available, so any content-gated gear is starting to become really cheap, too. It's still a good time to sell access to content for challenge-hunters, but don't expect to sell as much gear anymore. Exalts are usually at their highest price at this point.
4) week 4-5 = exodus. Most active players have done everything they wanted to do and are leaving PoE. Both demand and supply of items is starting to go down, and mostly only popular uniques sell more or less well. Still ok time to sell challenges, but demand goes down noticeably, and you can only really sell the hard-to-get ones. Player activity and demand become heavily dependent on streamer hype - if there's a new interesting build showcased, some people will return.
5) week 6+ = "dead" league. Low supply, low demand, few people playing. It becomes pretty hard to even buy some gear, so if you started this late, you might resort to overpaying for mediocre gear or playing semi-self-found. Also, the only reliably way to make currency is to simply depend on currency drops or to flip said currency.