Other way around: Easier tickets is an incentive for volunteers, as a bit of a payment in kind. It helps people known to volunteer come back, and it encourages them to keep volunteering year after year. You need to work, honestly, ridiculous amounts of hours to get a voucher (15-20 hours), and so it'd not be a very good incentive for average person.
You can absolutely get tickets on public sales by knowing when sales start, refreshing on the dot and doing the captcha as fast as you can. Reducing your latency (ethernet, fresh browser profile without extensions) helps. Add some friends into the mix and you'll get all the tickets you need.
Tickets are not that hard to get and you are not required to do anything once you have one.
I believe some core orga members (aka The people contracting the venue, getting permissions and renting equipment etc) are guaranteed a ticket but almost everybody else has to buy their own.
The fact that the "hacker space community" gets preferential treatment is very much intended.
