Here are just a few Evangelical sites that seem to disagree with your interpretation of the Bible on eternal security.
http://morechristlike.com/unbiblical-teachings/
http://morechristlike.com/are-errors-faults-and-mistakes-sin/
http://www.eternalsecurity.us/doctrinal_delusions_of_dave_hunt.htm
http://www.eternalsecurity.us/if_you_can_lose_your_salvation.htm
http://eternalsecurity.us/once_saved_always_saved%20a%20substitute%20for%20grace.htm
Is your reading of the Bible then a matter of taste?
Depends on the work of God the Holy Spirit within the believer. The doctrine of eternal security depends upon God’s integrity, not ours. We did nothing to earn our salvation and we can’t do anything to lose it. It is His decision and work in us.
Eph 2:8-10
(8) For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:
(9) Not of works, lest any man should boast.
(10) For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.
Yep, lots of people don’t remain in faith in Christ. Doubting their eternal security manifests a lack of faith. Those who doubt their eternal security never reach spiritual maturity and fail to receive many a blessing from the justice of God.
So if the doctrine doubting one’s security were sound, it would produce a self fulfilling prophecy of dooming its advocates to damnation.
On the contrary, we continue to grow in faith because our God is a living God, not a God of the dead.
If somebody falls out of fellowship after being saved, God the Holy Spirit by His volition (also known as His Sovereignty) still indwells the believer. God does nothing for no good.
He knew beforehand every sin we would ever commit even when He decided to give us eternal life by His grace.
For the believer, the issue isn’t judgment for salvation, it is the bema seat for eternal rewards predestined for us, upon review of our decisions in life.
There may be many who never have exercised simple faith alone in Christ alone, but have always coupled works or continuing effort to receive salvation, voiding the initial inkling they had to have faith alone in Christ. Then when they step away from doctrine, they discover they are in a void without God the Holy Spirit, leading them to conclude they can lose their salvation when they never had it in the first place.
Faith is a funny thing. Tomes have been written about it, but it only takes a smidgeon more faith than no faith whatsoever to have a saving faith alone in Christ alone.
Once saved, the issue isn’t sin or salvation, the issue is remaining in fellowship with Him, to further grow in Christ, to more glorify Him by being at the right place at the right time to do the right thing by His Plan.