Yes it could happen, but then again it just as easily couldn't. Some thing are more easily turned around than others. The players currently underperforming for England have no history of playing better for the Lions than they have for England.
The thing is - it was a gamble, a risk.
Someone taking a risk, that doesn't pay off has to expect the criticism. Equally, they've earned plaudits if it does come off.
Equally, each player has they're own risk / reward balance.
Mako has been poor for 18 months now; so was a big risk - the alternative to Mako would (should) have been Marler; who's better than Mako anywa. So it was a big risk, with no particular upside, but a big potential downside.
Itoje played well in the 6N, and is genuinely head and shoulders above the alternatives; so the risk was low - The alternative to Itoje would (should) have been Gray/Ryan; who are a step below him. So it was a small risk, with a high potential upside and low potential downside.
Billy has been poorish for 24-30 months now, with the last 12 months being frankly bad form, he also has known fitness / motivation issues; he is a huge risk - The alternative to Billy would have been... erm... nobody really, there's no-one else in world rugby who replicates what Billy does when he's in form, it's really not obvious who'd have taken his place if he wasn't invited. So it was a huge risk, with a huge potential upside, and no particular downside.
Farrell has been in poorish form for 12-18 months, and has ever been as good as his hype (though he does have some benefits off-field in leading the mindset); so was a significant risk - the alternatives to Farrell (on field) would (should) have been Ford / Sexton at FH or Slade at centre; all 3 are better than Farrell (though the former two weren't really fit to tour). So Farrell was a significant risk, who's potential upsides are mostly off the pitch, but small downsides as the alternatives aren't fit, and within the squad Biggar does what Farrell does, better.
Daly has been out of position and in poor form since he switched to FB. He's a big risk because he's not been taken to play the position he usually plays these days. He's a good centre and a very good winger when in form; and given that, his quality and rewards could switch on as easily as putting him in the right shirt (probably #23) - I realy don't know who'd have gone if he hadn't, but there aren't realy any names fro the back 4 who leap out as being harshly denied a tour spot. He's a risk, but it's impossible to judge how big, with big potential upsides, and kunknown potential downsides.
For me, Itoje and Daly are risks that were absolutely worth taking, Billy probably worth taking, even with a low chance of paying off.
On-field, Farrell probably wasn't worth taking, but would probably have had the call up after Ford / Sexton fail their medicals. Off-field is impossible for us fans to judge. Overall, worth taking. Either way, there was absolutely no chance of Gatland taking both Russell and Ford; he's simply allergic to the way those 2 play rugby. Either would only have gone because you need 3 FHs.
Mako was simply a bad call; and even if he does find form on tour, he still wouldn't have been as useful as his obvious replacement.