I don't know what you can do in your garage, but in my two car garage I can do:
* Basic blacksmithing (small furnace & anvil)
* Woodwork using power tools & manual tools (table saw, miter saw, router table, band saw, planer, etc)
* Metal working
* Ceramics casting
* Jewelry making
* 3D printing (resin and reel)
* Laser cutting (48 x 24)
* Vacuum forming
* Robotics
* Paint spraying (just bought a five stage paint blower)
* CNC (small format, would like to add a 5-axis eventually)
* Shoot build videos
* Electronics design & diagnostics (just finished my new ESD workbench with component storage)
* Laundry
* Mini-CostCo with freezer section
Will be adding a 48x48 CNC in the coming weeks, once I finish some more cabinets
What I cannot do in my garage:
* Park a car
* Find enough time to do what I want
If you've got a 4x8 CNC and/or large format laser cutter, you pretty much have a small business at that point. It is then up to you how you monetize it.
That's not a garage, that's better equipped than many hacker spaces where people pool money to finance shared equipment. This is not like an ordinary thing everyone can just do if they want to, at least not if it's not part of a business plan to manufacture a particular thing with it.
What I cannot do in my garage:
If you've got a 4x8 CNC and/or large format laser cutter, you pretty much have a small business at that point. It is then up to you how you monetize it.