Entire point of what Paul was saying, is that we should not boast, that we need God's grace to be saved as we are only human and can not do it alone. Because as Jesus said with man this is impossible, but with God all things are possible. But you use the talents of Matthew 25, but ignore the last half of the parable that talks about the servant that does no works with the 1 talent and the Master returns and takes his talent away and tosses him into outer darkness. James tells us faith without works is dead. You should also read the parable of the sower, of people that hear the truth with the gift of faith but reject it because they chose this life over God. There are many examples of works earn salvation but it is ignored with all the defending of a tradition of man out of fear because Christians rather live a lie of "once saved always saved even if I rape and murder 5 million people", because they do not trust God or believe in themselves that they can get to Heaven without a free lazy pass.
Paul and James are not inconsistent. Salvation IS by grace alone, but it is most assuredly true that a true faith...one that has regenerated the heart, is accompanied by fruit. If a person is not showing this fruit, one must wonder if the regeneration was genuine.
And we see this in, as you say, the parable of the sower, and also as it is played out even in our Churches. People come and hear the word of God, hear the truth! Many people even seem to recognize that there is truth to it, that there is rightness to it...but sadly it is not enough, not without the Spirit doing his work as well. The parable tells us that without the supernatural work of the Spirit, life and its cares, or Satan and his snares, snatches the truth away from these people.
Haven't you witnesses the same thing? The truth, the powerful, wonderful, freeing truth that you know holds so much power and freedom, and people just can't understand it, or hold it as precious. They smile at it, and maybe flirt with it, take it to lunch, but they just don't find it worthy to commit to. It hasn't grabbed them as the most important thing in the world, worth throwing every other thing away for! It's only God's regenerating work in a person that leads a person to WANT to do that!
So, regardless of what people say, or where they go on Sunday's or even if they attend bible study's...we look to what harmonizes....do their words match up with their actions? That's the point of what James wrote. Paul is right...grace IS a gift...it HAS to be a gift. But James is right too...when that gift has been fully received in a person's life, it will change them and result in fruit, in outwards actions.
If someone knows they lack works and are not living righteously to the point the create a false doctrine to ease their fears of what awaits them, then they already know their fate and where they are going but God will not intervene. This life is a test, a trial of our faith, and narrow is the way. There is no test to be given a free gift, then sit watch tv until you die. Nonsense born of people knowing the fate that awaits them and it scares them.
It's only nonsense if its not found in scripture. The problem is; it is. Grace IS a free gift. It has to be for two reasons: one...man is incapable of earning grace via his own works, even if he wanted to or tried to. And two...if grace if a free gift, then ALL the glory and praise goes to Christ and him alone.
Please note, however, that only disingenuous or false 'Christians' promote the idea of being 'lazy' or 'depending on grace so they can sin more'. That is not what scripture teaches, and it is not what honest regeneration produces anyway.