It may be just that he realizes that he's at some risk of other criminal charges (e.g. for laundering for the gox hacker) and ultimately paying up may not save him from spending his life on the run, and if you're going to be on the run away-- why pay?
How stupid can you really think he is when he walked free and ended up not paying more in taxes than he originally should have-- and had the opportunity to benefit from an extra decade of bitcoin appreciation and the potential that he could have gotten away with it entirely? I mean call him stupid if you want but I bet he can't hear you over the pile of money that his 'stupid' tactics earned him.
Sure Ver has been involved in so many ways to "invest" in bitcoin-related businesses and activities over the years, so it could be question able the extent to which he was able to hold onto good portions of his BTC stash including likely losing leveraging that he was doing to support and/or attempt to prop up Bcash - and even in the 2022 crashening times, weren't there rumors that he had some naked margin bets (meaning no collateral) that he failed/refused to pay some exchange when the bets had gone against him.. .so the exchange ended up holding Ver's bags, which might mean he was unable to pay, but still since we know Roger has various self-absorbed (and quasi-delusional) conniving angles to his personality, he may well could have had been unwilling to pay rather than unable to pay.
As you mentioned, surely Ver was able to considerably profit from his failure to pay, and even though it can be difficult to sympathize for the government, Bitcoin's appreciation did seem to disproportionately advantage Ver rather than the government, yet we are put into a tough position to argue that the government should have had gotten more and surely lucky for Ver to negotiate staying out of Jail. Accordingly, it does seem to be the case that the USA government counted the tax that was due in dollars and even if they doubled the amounts for various penalties, Ver was able to still considerably profit from Bitcoin's upside by not having to sell some of his bitcoin to satisfy the tax payment when it was actually due.
I tend to think that it tends to be better when settlements can be reached, but yeah, Roger has some questionable past behaviors that might end up catching up with him, yet at the same time, anyone who is a public figure and also potentially funding various projects, there can be questions regarding the various account, and it can be quite a pain in the ass to engage in various kinds of accounting. .which maybe some of us might consider that it is not such a bad thing to have questionable accounting if the money ultimately goes to good causes such as funding some kind of development or activity that might be under represented and not getting funding... but then sometimes the matters being funded might be questionable as well... and it can take a bit of sleuthing to figure out some of the relationships regarding who is funding who and for what kinds of "business" activities?
~snip~
It may be just that he realizes that he's at some risk of other criminal charges (e.g. for laundering for the gox hacker) and ultimately paying up may not save him from spending his life on the run, and if you're going to be on the run away-- why pay?
How stupid can you really think he is when he walked free and ended up not paying more in taxes than he originally should have-- and had the opportunity to benefit from an extra decade of bitcoin appreciation and the potential that he could have gotten away with it entirely? I mean call him stupid if you want but I bet he can't hear you over the pile of money that his 'stupid' tactics earned him.
I don't know how much BTC he actually has today, but the whole thing is about 131 000 BTC which were worth about $7.5 billion at the time of his arrest, and are worth twice that today. Assuming he only owns 10% of it today, it doesn't seem smart to me to spend 1.5 years in prison for the $50 million he was supposed to pay.
That is the thing with bitcoin, it might still be difficult to be positive about the totals - except to the extent that Ver might have had admitted to some of the totals or if the evidence is fairly strong about ownership. We frequently might not know who to trust regarding the numbers, yet calculating that he could have screwed up a lot, and he ONLY retains about 10% of the coins that he owned 10-ish years ago, then 131k bitcoin had gone down to 13.1k bitcoin (today's price of around $1.4 billion), so if that were true, he still would have quite a bit of value to work with... and in those circumstances, $50 million-ish seems within reason to be able to stay out of jail for this case (to the extent that he does not have other matters, like Greg points out).
Who knows, maybe he actually liked the Spanish prison and wanted to extend his stay as much as possible

I doubt that Ver wants to be in prison, and surely it could be the case that the US government were not really negotiating with Roger in good faith (as Roger alleges), yet we likely have to take Roger's representations with a grain of salt, since historically he has shown himself to have tendencies to exaggerate and spin within situations that we know the evidence, so then if we do not know the evidence, it can be problematic to rely upon Roger's version of events.