I've been having a conversation with the folks at Ootinicast, who are celebrating their 100th episode this week, about the latest changes to SWTOR. My thoughts don't really fit into an email that anyone would want to hear read aloud on a podcast, and I've mangled them slightly by trying.
At a minimum, Bioware appears to feel that keeping players out of current endgame content is not worth the modest amounts of money they previously charged for access. In the longer term, I think Bioware is trying as hard as they can to have more of their money come from people subscribing to partake in traditional MMO endgame staples that are more sustainable than the game's famous story content.
Content Sales, or lack thereof
The core of Bioware's re-launched model is to use their content to sell subscriptions, rather than selling their content. Games that have succeeded on a content sales model are generally able to deliver small releases of highly repeatable content every 2-3 months. If people are only paying you when you have content (new or old) that they want to play available - whether that's a one-time payment as in LOTRO and other games or a subscription that players only pay to see the next chapter in the Sith Warrior story - and you cannot maintain that release pace, you are going to have problems getting paid.
Bioware launched the game's first expansion - with the only significant new story content to date - back in April at a cost of $10 for subscribers and $20 for non-subscribers. Five months later, subscribers get permanent access to the expansion for free (even after their subscription lapses), making it cheaper for non-subscribers to pay for a $15 one-month subscription (which includes 500 Cartel Coins) than purchase the expansion at full price. This could be a routine mark-down/discount (albeit unusually early compared to other games' expansions), but I feel it's worth considering Bioware's patch strategy as well.
At the Free to Play relaunch, Bioware implemented a fee for non-subscribers to access Section X, a new daily quest area that also offered a new NPC companion. This may not have been a great test case - as the Ootini crew point out, it's the least popular of the pre-expansion daily quest areas, and Bioware gave away the unlocks in random Cartel Packs to subscribers who had no use for them and therefore resold them for trivial prices on the auction house. Good test case or not, though, there was no fee for a new daily quest area added in patch 2.3 and to my knowledge no fee planned for new content - including some story - scheduled for patch 2.4.
Towards the endgame
A for-profit company does not reduce or eliminate fees that are successfully generating revenue unless there is some other consideration. If newly level 50 players were routinely taking out their credit cards and paying for the expansion then there'd be no need to change the pricing. The alternative is that significant numbers of eligible accounts have declined to purchase the expansion.
Because the expansion is tied to a level cap increase, not paying that fee means not having access to current group content and not having access to new daily quests and revised world events in new patches. Likewise, counterintuitive as it may seem, I believe you can be a subscriber and still represent short term revenue for Bioware if you are only paying to solo the story content. Such a player is unlikely to pay extra for access to a daily quest area with little new story. In both cases, Bioware may be hoping that the player will ultimately pay for more game time if given the content for free.
Damien Schubert once told the Ootinicasters that he would like to develop Capital Ships as guild housing in SWTOR - during that conversation, he admitted that part of the development process would have to consider how Bioware could expect to make money off of the project. This is why this seemingly academic question may matter to the game's full-time subscribers.
Endgame PVE can't suffer exactly the same fate as ranked 8-player warzones (axed after months of promises of attention to the format this fall) or craftable cosmetic gear (all reserved for the cash shop henceforth), but the level of emphasis it gets can definitely shift based on where the money is. The less money Bioware can rake in at endgame, the larger the portion of their effort they will need to shift to stuff that is open at lower levels and thus able to be paid for by more of the playerbase. Coincidence that the game is now working on a revamp to space combat that will very likely be open well before max level? Time will tell.