What do you mean with 10 times less budget? RIFT cost about
$50,000,000 at minimum (real costs est. around close to $60,000,000 actually). 10 times as much would be around 500m.
It also took around 5 years to make.
Considering both MMOs are using different architectural layouts they are not comparable at base. Trion's investment is VC-based (they started off with around $350m which they spread over several games) so they naturally took alot of conservative routes, that probably meant on spending side they couldn't be as generous. Usually - and I am going by experience in a similarly grown company - that means that people have to work with less for more under less-than-ideal circumstances for that one goal of success with alot of shared resources as well. A company like EA would just recoup the losses elsewhere and have no problem with lay-offs in order to survive whereas a company like Trion only has this chance or face closure.
Either way the entire nature of your question is why they accomplished more with less, the real answer lies within the fact that most internal things will always remain undisclosed that includes the decision processes, management sessions, how many times they had to start over things, how many people they had to hire, lay off, what challenges they had to face etc. Also some of the things which Bioware had to overcome were no issue for Trion, like synchronized event scripting, whereas Bioware didn't have to deal with issues unique for Trion such as dynamic world events affecting players. In short: it's not comparable on 1:1 basis, chances are that if roles were reversed none of both may come out better. Bioware made a controversial decision on engine part, Trion made a controversial decision on security part, I don't know - I will take the first over the latter any day.
Besides RIFT didn't have alot of things at launch either (no addons, no LFG tool, no guild banks etc.), alot of features were inserted post-production, I have been playing it as well so I pretty much know how it went and I don't tend to hold it against them. Because companies which listen to their playerbase usually try to cater to the demands, alot demands perceived as standard features are/were not always seen the same way by its developers. It's a matter of view really, you can also find these views being reflected by parts of the playerbase. Case in point: On-going fierce debates about LFG tool, addons/macros and respecs in SW:TOR.