I think you've no idea what commuting costs anymore. 100 a week would be absolutely ridiculous. If the company provides parking you're looking at around 70 per month. If you have to pay for parking that might be as much as 250 per month, so still way below 100 per week. This kind of contribution certainly adds up, but you're not looking at 1 million in retirement funds. Also, you built yourself a detached office, which isn't uncommon and you frequently needed to purchase office supplies and I'm guessing your own hardware and computer software. That's a substantial initial overhead that eats away at how much you might be saving by working from home.
Also, consider that many companies now allow employees to work from home for part of every week while still supplying hardware and office supplies. That 250/70 per month commuting cost is down to about 150/40. Just accounting for the expense of building your home office you could already be in the hole compared to people commuting only some of the time for the same job.
Also, none of this accounts for the additional considerations office's typically provide like free lunches and social/professional networking opportunities.
Personally, I'm a software developer so I can pretty much decide for myself if I want a job that allows me to work from home, and after doing the real math, I found you can basically go either way and expect roughly the same financial outcome, so the real choice is about what you actually want. I like the social aspects, so I take jobs where I can come in and expect coworkers to be present. What you want may be different, but neither option is inherently more advantageous.