I clearly remember that booting Windows 95 on my 386SX was under one minute. I remember measuring this.
The 386SX ran at 16 MHz, was seven years old at the release of Windows 95 and was slightly below the stated minimum system requirements. By contrast, I had a 166 MHz Pentium (released four months after Windows 95) and I remember it being slow enough that I would go do something else while it booted.
I see references that mention that installing fonts can significantly impact boot time. Maybe the installed software and devices had a significant impact.
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And significantly less reliable.
Remember how common crashes were? (Including BSoD!)
Like, you can solve 90% of memory crashes by using a memory managed language but that is course has costs.